# kb

id: glossary-of-economics-20260505-3
file: data/en.wikipedia.org/wiki/Glossary_of_economics-3.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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parent: glossary-of-economics-20260505-0
summary:
biflation Also called mixflation. A state of the economy in which the processes of inflation and deflation occur simultaneously in different parts of the economy. big push model A concept in development economics or welfare economics that emphasizes that a firm's decision whether to industrialize or not depends on its expectation of what other firms will do. It assumes economies of scale and oligopolistic market structure and explains when industrialization would happen. Birmingham school A school of thought based around opposing the gold standard, advocating for expansionary monetary policy, and belief in underconsumption. Bishop–Cannings theorem A theorem in evolutionary game theory that states that (i) all members of a mixed evolutionarily stable strategy have the same payoff, and (ii) that none of these can also be a pure ESS. Black–Scholes model Also called the Black–Scholes–Merton model. A mathematical model for the dynamics of a financial market containing derivative investment instruments. From the partial differential equation in the model, known as the Black–Scholes equation, one can deduce the Black–Scholes formula, which gives a theoretical estimate of the price of European-style options and shows that the option has a unique price regardless of the risk of the security and its expected return


id: glossary-of-economics-20260505-4
file: data/en.wikipedia.org/wiki/Glossary_of_economics-4.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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parent: glossary-of-economics-20260505-0
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business cycle Also called the economic cycle or trade cycle. The downward and upward movement of gross domestic product (GDP) around its long-term growth trend. The length of a business cycle is the period of time containing a single boom and contraction in sequence. These fluctuations typically involve shifts over time between periods of relatively rapid economic growth (expansions or booms) and periods of relative stagnation or decline (contractions or recessions). business economics A branch of applied economics which uses economic theory and quantitative methods to analyze business enterprises and the factors contributing to the diversity of organizational structures and the relationships of firms with labour, capital and product markets. business sector Also called the corporate sector or sometimes simply business. The part of the economy made up by companies. It is generally considered a subset of the domestic economy, excluding the economic activities of general government, of private households, and of non-profit organizations serving individuals. == C == Cambridge capital controversy Also called the capital controversy or the two Cambridges debate. A dispute between proponents of two differing theoretical and mathematical positions in economics concerning the nature and role of capital goods and a critique of the neoclassical vision


id: glossary-of-economics-20260505-5
file: data/en.wikipedia.org/wiki/Glossary_of_economics-5.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
instance: kb-cron
parent: glossary-of-economics-20260505-0
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cash Money in the physical form of currency, such as banknotes and coins. cash crop A cash crop, also called profit crop, is an agricultural crop which is grown to sell for profit. It is typically purchased by parties separate from a farm. central bank Also called a reserve bank or monetary authority. An institution that manages the currency, money supply, and interest rates of an entire state or nation. Central banks also usually oversee the commercial banking system of their respective countries. In contrast to a commercial bank, a central bank possesses a monopoly on increasing the monetary base in the state, and usually also prints the national currency, which usually serves as the state's legal tender. Central banks also act as a "lender of last resort" to the banking sector during times of financial crisis. Most central banks usually also have supervisory and regulatory powers to ensure the solvency of member institutions, prevent bank runs, and prevent reckless or fraudulent behavior by member banks. Certificate of Deposit (CD or COD) A savings instrument that usually earns more interest than a savings account but is bound by limits set within a contract. ceteris paribus A phrase or clause often


id: glossary-of-economics-20260505-6
file: data/en.wikipedia.org/wiki/Glossary_of_economics-6.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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parent: glossary-of-economics-20260505-0
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command economy An economy in which the government directs all economic activity. commerce Relates to "the exchange of goods and services, especially on a large scale". It includes legal, economic, political, social, cultural and technological systems that operate in a country or in international trade. commercial agriculture It is a type of agriculture, both of crop plants and of animals, with higher levels of input and output per unit of agricultural land area. commodity An economic good or service that has full or substantial fungibility: that is, the market treats instances of the good as equivalent or nearly so with no regard to who produced them. communism An ideology centered around common ownership of the means of production, distribution, and exchange that allocates products to everyone in the society based on need. comparative advantage Also called opportunity cost advantage. The ability to produce most efficiently given all of the other products that could be produced. compensating differential Also called compensating wage differential or equalizing difference. The additional amount of income that a given worker must be offered to motivate them to accept a given undesirable job, relative to other jobs that worker could perform. Competition (CD or COD) The presence


id: glossary-of-economics-20260505-7
file: data/en.wikipedia.org/wiki/Glossary_of_economics-7.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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parent: glossary-of-economics-20260505-0
summary:
consumption function A mathematical function which describes a relationship between consumption and disposable income. The concept is believed to have been introduced into macroeconomics by John Maynard Keynes in 1936, who used it to develop the notion of a government spending multiplier. contract curve In microeconomics, the contract curve is the set of points representing final allocations of two goods between two people that could occur as a result of mutually beneficial trading between those people given their initial allocations of the goods. All the points on this locus are Pareto efficient allocations, meaning that from any one of these points there is no reallocation that could make one of the people more satisfied with his or her allocation without making the other person less satisfied. The contract curve is the subset of the Pareto efficient points that could be reached by trading from the people's initial holdings of the two goods. contract theory The study of how economic actors can and do construct contractual arrangements, generally in the presence of asymmetric information. Because of its connections with both agency and incentives, contract theory is often categorized within a field known as law and economics. convergence Also called the catch-up


id: glossary-of-economics-20260505-8
file: data/en.wikipedia.org/wiki/Glossary_of_economics-8.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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parent: glossary-of-economics-20260505-0
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cost-push inflation A purported type of inflation caused by increases in the cost of important goods or services where no suitable alternative is available. As businesses face higher prices for underlying inputs, they are forced to increase prices of their outputs. credit bureau An agency that tracks the credit, employment, and housing history of consumers and assigns them a credit score. credit card A payment card issued to users (cardholders) to enable the cardholder to pay a merchant for goods and services based on the cardholder's promise to the card issuer to pay them at a later time for the cost of the good or service plus other agreed-upon fees and charges. The card issuer (usually a bank) creates a revolving account and grants a line of credit to the cardholder, from which the cardholder can borrow money for payment to a merchant or as a cash advance. credit score A numerical value assigned to a person's potential ability to repay debt. A good credit score in the United States is approximately 700. credit rating An evaluation of the credit risk of a prospective debtor (an individual, business, company, or government), predicting their ability to pay back the debt, and


id: glossary-of-economics-20260505-9
file: data/en.wikipedia.org/wiki/Glossary_of_economics-9.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
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parent: glossary-of-economics-20260505-0
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deficit spending Also called budget deficit or simply deficit. The amount by which spending exceeds revenue over a particular period of time; it is the opposite of budget surplus. The term may be applied to the budget of a government, private company, or individual. deflation A decrease in the general price level of goods and services. Deflation occurs when the inflation rate falls below 0% (a negative inflation rate); though inflation reduces the value of currency over time, deflation increases it. This allows more goods and services to be bought than before with the same amount of currency. Deflation is distinct from disinflation, which occurs when the inflation rate decreases but is still positive. deflator A value that allows data to be measured over time in terms of some base period, usually through a price index, to distinguish between changes in the money value of a gross national product (GNP) that come from a change in prices, and changes from a change in physical output. It is the measure of the price level for some quantity. A deflator serves as a price index in which the effects of inflation are nulled. It is the difference between real and nominal GDP.


id: glossary-of-economics-20260505-10
file: data/en.wikipedia.org/wiki/Glossary_of_economics-10.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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parent: glossary-of-economics-20260505-0
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discretionary income Money available after one pays taxes and all other necessary expenses like housing and transportation. disequilibrium macroeconomics Also called non-Walrasian theory, equilibrium with rationing, the non-market clearing approach, and non-tâtonnement theory. A tradition of research centered on the role of disequilibrium in economics. disinflation A decrease in the rate of inflation; a slowdown in the rate of increase of the general price level of goods and services in an economy's gross domestic product over time. It is the opposite of reflation. Disinflation is also distinct from deflation, which occurs when the inflation rate is negative. dispersed knowledge The notion that no single agent has information as to all of the factors which influence prices and production throughout the system. disposable income Money available after one pays taxes; income available for personal consumption and saving. disposition effect The tendency to sell an asset that has accumulated in value and resist selling an asset that has declined in value. dissaving Negative saving, which occurs when spending is greater than disposable income. This spending may be financed by already accumulated savings, such as money in a savings account, or it can be borrowed. distribution The way total economic output, income, or


id: glossary-of-economics-20260505-11
file: data/en.wikipedia.org/wiki/Glossary_of_economics-11.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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economic base analysis A theory that posits that activities in an area divide into two categories: basic and nonbasic. Basic industries are those exporting from the region and bringing wealth from outside, while nonbasic (or service) industries support basic industries. economic calculation problem (ECP) A criticism of using economic planning as a substitute for market-based allocation of the factors of production. It is argued that economy planning necessarily leads to an irrational and inefficient allocation of resources. economic cost The combination of losses of any goods that have a value attached to them by any one individual. Economic cost is used as means to compare the prudence of one course of action with that of another. economic democracy Also called a democratic economy. A socioeconomic philosophy that proposes to shift ownership and decision-making power from corporate shareholders and corporate managers (such as a board of directors) to a larger group of public stakeholders that includes workers, consumers, suppliers, communities and the broader public. economic development Broad improvement in the economic well-being or quality of life of a nation, region, or community, often but not necessarily as a consequence of economic growth. economic efficiency A variety of concepts which denote some


id: glossary-of-economics-20260505-12
file: data/en.wikipedia.org/wiki/Glossary_of_economics-12.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
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parent: glossary-of-economics-20260505-0
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economies of scope The cost advantages that enterprises obtain as a result of the increased efficiency offered by variety rather than by volume, with cost per unit of output decreasing with increasing variety. In economics, "scope" is synonymous with broadening production through diversified products. For example, a gas station that sells gasoline can also sell soda, milk, baked goods, etc. through their customer service representatives, which may make the sale of gasoline more efficient. economist A practitioner in the discipline of economics. economy An area of the production, distribution, trade, and consumption of goods and services by different agents. In its broadest sense, an economy may be defined as "a social domain that emphasizes the practices, discourses, and material expressions associated with the production, use, and management of resources". Edgeworth box Also called an Edgeworth-Bowley box. A graphical representation of a market with just two commodities, X and Y, and two consumers. The dimensions of the box are the total quantities Ωx and Ωy of the two goods. Edgeworth paradox A situation in which two players cannot reach a state of equilibrium with pure strategies, i.e. each charging a stable price. It was proposed to solve the Bertrand paradox. Edgeworth's


id: glossary-of-economics-20260505-13
file: data/en.wikipedia.org/wiki/Glossary_of_economics-13.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
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equilibrium The point at which quantity demanded and quantity supplied are equal and both consumer and producer are satisfied. equilibrium price The market price at which both the supplier and consumer will trade and both are satisfied. equity Also called economic equality. The concept or idea of fairness in economics, particularly in regard to taxation or welfare economics. More specifically, it may refer to equal life chances regardless of identity, to provide all citizens with a basic and equal minimum of income, goods, and services or to increase funds and commitment for redistribution. equity home bias puzzle The fact that individuals and institutions in most countries hold only modest amounts of foreign equity, and tend to strongly favor company stock from their home nation. This finding is regarded as puzzling, since ample evidence shows equity portfolios obtain substantial benefits from diversification into global stocks. equity premium puzzle The inability of an important class of economic models to explain the average equity risk premium provided by a diversified portfolio of equities over that of government bonds, which has been observed for more than 100 years. ergodicity economics A research programme aimed at reworking the theoretical foundations of economics around the concept


id: glossary-of-economics-20260505-14
file: data/en.wikipedia.org/wiki/Glossary_of_economics-14.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
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parent: glossary-of-economics-20260505-0
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finance The study of money and how it is used. Specifically, it deals with the questions of how an individual, company, or government acquires the money needed—called capital in the company context—and how they then spend or invest that money. Finance is often split into three areas: personal finance, corporate finance, and public finance. At the same time, finance is about the overall "system", i.e. the financial markets that allow the flow of money, via investments and other financial instruments, between and within these areas; this "flow" is facilitated by the financial services sector. A major focus within finance is thus investment management—called money management for individuals, and asset management for institutions—and finance then includes the associated activities of securities trading, investment banking, financial engineering, and risk management. financial deepening financial economics financial institution Any firm, such as a bank, that is in the business of holding money for those who save and lending money to those who need loans. financial markets Markets where people trade the property rights to assets (like real estate or stocks) or where savers lend money to borrowers. financial planning A series of steps used by a person or a firm to achieve a financial


id: glossary-of-economics-20260505-15
file: data/en.wikipedia.org/wiki/Glossary_of_economics-15.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
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history of economic thought The study of the history of the philosophies of the different thinkers and theories in the subject known today as economics, from ancient economic thought to contemporary economic thought. Hodrick–Prescott filter Holmström's theorem home bias in trade puzzle home bias puzzle homo economicus Hotelling's law Hotelling's lemma hourglass economy household The sector of the economy which purchases goods from the product market and sells labor, land, and entrepreneurship ability to the factor market in the circular flow market. housing starts The number of new houses being built during a period of time. Huff model human capital The knowledge and skills that people use to help them produce output. human capital flight humanistic economics hyperinflation Inflation which occurs at an extremely high rate, usually in excess of 20 or 30 per cent per month. == I == Icarus paradox immiserizing growth implicit cost import import substitution industrialization import quota impossible trinity imputation Inada conditions incentive income income distribution income effect The change in consumption resulting from a change in income. income elasticity of demand (YED) Measures the sensitivity of a good's demand to income. Income tax A tax levied on income, weather being on an individual or


id: glossary-of-economics-20260505-16
file: data/en.wikipedia.org/wiki/Glossary_of_economics-16.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
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leprechaun economics Distortion of national accounts data by corporate tax schemes. Lerman ratio Lerner index An index ranging from 0 to 1 that measures a firm's market power given the price it sets and its marginal cost. Lerner paradox Lerner symmetry theorem Lewis–Mogridge position liability Financial responsibility for something. liberal paradox limit price loan local multiplier effect Also called the local premium The additional economic benefit accrued to a geographic area from money being spent in the local economy. local tax Any tax paid to a city or county, e.g. sales taxes, school taxes, or property taxes. location model long run long-run shutdown condition A situation where a firm's total revenues exceed its variable costs but are less than its total costs. The firm continues to operate until its fixed cost contracts expire. long-term financing LoopCo loose money policy A monetary policy that makes credit inexpensive and abundant, possibly leading to inflation. Lorenz curve loss aversion Lucas critique Lucas paradox Lundberg lag luxury good == M == macroeconomic model macroeconomic policy instruments macroeconomic populism macroeconomic regulation and control macroeconomics The study of the economy as a whole, concentrating on economy-wide factors such as interest rates, inflation, and unemployment. Macroeconomics also


id: glossary-of-economics-20260505-17
file: data/en.wikipedia.org/wiki/Glossary_of_economics-17.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
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monopoly A firm with no competitors in its industry. A monopoly firm produces less output, has higher costs, and sells its output for a higher price than it would if constrained by competition. monopsony moral hazard mortgage motivation moving equilibrium theorem multiplier multiplier uncertainty Any lack of perfect knowledge of the multiplier effect of a particular policy action, such as a monetary or fiscal policy change, upon the intended target of the policy. Mundell–Fleming model mutual fund mutual fund separation theorem mutualism == N == Nakamura number Nash equilibrium national average salary national income and product accounts national income policy agreement national tax Any tax paid to a national or federal government, e.g. income tax, tariffs, and social security taxes. national wealth The total value of capital and private property that is owned within a country. natural monopoly An industry in which one large producer can produce output at a lower cost than many small producers. It undersells its rivals and ends up as the only firm surviving in its industry. natural resource economics need Any good or service that is fundamentally necessary for survival, such as food, clothing, and shelter. Neoclassical economics Neoclassical synthesis Neoliberalism Neo-Ricardianism Neo-Schumpeterian economics net


id: glossary-of-economics-20260505-18
file: data/en.wikipedia.org/wiki/Glossary_of_economics-18.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
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price elasticity of demand (PED) Measures the sensitivity of a good's demand to its price. price elasticity of supply (PES) Measures the sensitivity of a good's supply to its price. price floor A market intervention in which the government keeps the price of a good or service above its free-market price. price index A normalized average of price relatives for a given class of goods or services in a given region and during a given period of time. It is a statistic designed to help to compare how these price relatives, taken as a whole, differ between geographical locations or time periods. Notable price indices include consumer price index, producer price index, and GDP deflator. price level price point price–specie flow mechanism price war pricing pricing science The application of social and business science methods to the problem of setting prices. primary economic activity An economic activity which is focused on the extraction of natural resources of the earth. prime rate Also called the prime lending rate. The interest rate at which a bank will agree to lend to customers with good credit. Floating interest rates are often expressed as a percentage above or below the prime rate. principal–agent problem


id: glossary-of-economics-20260505-19
file: data/en.wikipedia.org/wiki/Glossary_of_economics-19.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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parent: glossary-of-economics-20260505-0
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resource market (Also known as a factor market.) In the circular flow model, the sector which facilitates resources from household to firms in return for income payment. retail sales Purchases of finished goods and services by households and firms. returns to scale revealed comparative advantage revealed preference revenue Total income from sales of output. Revolving Credit Revolving credit is a line of credit that remains available over time, even if the balance is paid in full. Borrowers can access credit up to a certain amount and then have ongoing access to that amount. Ricardian economics Ricardian equivalence Ricardian socialism rights right to work law A state law forbidding labor unions from forcing workers to join and pay union dues. risk aversion risk premium risk-return relationship The direct relationship between the risk of an investment and its expected return or profit; the higher the risk, the higher the opportunity for gain or loss and vice versa. rivalry Robin Hood effect Robinson Crusoe economy Robustness The ability of a financial trading system to remain effective. Rostovian take-off model Rostow's stages of growth Roth 401k A Roth 401(k) is an employer-sponsored retirement savings account that is funded using after-tax dollars. This means that


id: glossary-of-economics-20260505-20
file: data/en.wikipedia.org/wiki/Glossary_of_economics-20.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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supply-side economics A theory in macroeconomics which postulates that lowering tax rates, decreasing government regulation, and allowing free trade is the most effective way to foster economic growth because greater supplies of goods and services at lower prices cause employment to increase and consumers to spend more. Contrast demand-side economics. surplus A situation in which supply is greater than demand, usually as the result of high prices. == T == tableau économique tatonnement tariff Also called duty. A tax imposed by the government of a country, or by a supranational union of countries or institutions, on imports or exports of goods. Import duties may serve as a source of revenue for the government as well as a form of regulation of foreign trade by taxing foreign products to encourage or safeguard domestic industries that produce the same or similar products. Along with import and export quotas, tariffs are among the most commonly used instruments of protectionism. tax tax-benefit model tax benefits of debt tax credit tax deduction tax rate taxable income The amount of income that is subject to being taxed. This amount may or may not be the total gross income of a person or firm. Taylor rule technological


id: glossary-of-economics-20260505-21
file: data/en.wikipedia.org/wiki/Glossary_of_economics-21.md
category: reference
title: Glossary of economics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_economics
date_saved: 2026-05-05T07:50:44.577515+00:00
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parent: glossary-of-economics-20260505-0
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wealth The abundance of valuable financial assets or physical possessions which can be converted into a form that can be used for transactions. This includes the core meaning as held in the originating old English word weal, which is from an Indo-European word stem. The modern concept of wealth is of significance in all areas of economics, especially for growth economics and development economics, yet the meaning of wealth is context-dependent. Individuals or companies possessing a substantial net worth are often referred to as wealthy. Net worth is defined as the current value of one's assets less liabilities (excluding the principal in trust accounts). wealth effect The change in spending that accompanies a change in perceived wealth. Usually the wealth effect is positive: spending changes in the same direction as perceived wealth. welfare A type of government support for the citizens of that society. Welfare may be provided to people of any income level, as with social security (and is then often called a social safety net), but it is usually intended to ensure that people can meet their basic human needs such as food and shelter. Welfare attempts to provide a minimal level of well-being, usually either a free-


id: glossary-of-electrical-and-electronics-engineering-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-0.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
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parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
This glossary of electrical and electronics engineering is a list of definitions of terms and concepts related specifically to electrical engineering and electronics engineering. For terms related to engineering in general, see Glossary of engineering. == A == AC adapter An external power supply for portable devices that allows them to operate from wall-socket electricity. AC power plugs and sockets Electrical connectors used with alternating current. AC power Electric power where the current reverses direction periodically. AC-to-DC conversion (rectifier) Rectification of AC current, so that current flows in only one direction. AC-to-AC converter A power converter where the input and output are both in the form of alternating current (AC), but may differ in frequency or other characteristics. AC/DC receiver design A radio receiver that can operate from either alternating current or direct current wall socket power. active rectification A circuit where rectifier devices are externally controlled to change AC to current flowing in one direction. actuator An end device of a control system that manipulates a physical variable such as a valve opening or the position of a machine part. adaptive control A control strategy where parameters are adjusted as the controlled process changes. additive white Gaussian noise A


id: glossary-of-electrical-and-electronics-engineering-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-1.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
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parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
automatic gain control A circuit that automatically adjusts the magnitude of a signal to prevent it from becoming too small or too large. automatic transfer switch An electrical switch used to automatically select a standby source of electrical power when the principal source is lost. automation Automatic control of a process. autorecloser A circuit protection device for overhead power distribution lines which briefly interrupts a circuit when a fault is detected, then restores the circuit in the expectation the fault has cleared. autotransformer A transformer where the primary and secondary circuits share some of the transformer windings. availability factor The fraction of time that a power plant is available to produce power. avalanche diode A diode intended for regular operation in the reverse, avalanche breakdown, mode. Used as a voltage reference, noise source, and in certain classes of microwave oscillator device. average rectified value The average value of an alternating current waveform, taking the absolute value of the waveform. The average value is generally different from the root-mean-square value. == B == backward wave oscillator A type of micowave oscillator vacuum tube. balanced line A transmission line with two conductors, with equal impedances to earth ground. ball bearing motor A


id: glossary-of-electrical-and-electronics-engineering-20260505-2
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-2.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
Category 3 cable A performance standard for unshielded twisted pair cables for analog voice and low speed data circuits within a building. Category 5e cable A performance standard for unshielded twisted pair cables for telephone and data within a building. Category 6 cable A performance standard for unshielded twisted pair cables for telephone and high speed data within a building. catenary A geometric form of curve, the shape of a uniform cable hanging between two supports. cathode ray oscilloscope An electronic instrument that displays the wave shape of electrical signals on a cathode ray tube. cathode ray tube A vacuum tube that relies on an electron beam – usually used to render images on a fluorescent screen such as in television sets. cathode The terminal of an electrochemical or electronic device from which conventional current exits the device. cat's-whisker detector A radio detector that uses a manually-set "whisker" contact to a crystal of galena or other material, to form a rectifying junction. CATV Cable television, distribution of television programming over a wire instead of by radio broadcast. cavity magnetron A vacuum tube that is a high power microwave oscillator, using a resonant cavity and electrons traveling through a magnetic field.


id: glossary-of-electrical-and-electronics-engineering-20260505-3
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-3.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
consumer electronics Electronic devices intended to be owned by consumers directly; a mobile cell phone is "consumer electronics" but the cell site it communicates with is not. contactor An automatically controlled electrical switch (relay), used to operate motors or other high-current loads. continuous Fourier transform A mathematical operation that expresses a signal in time as the sum of its frequency components. continuous signal A signal that can take any value within its range. control engineering The application of control theory to practical problems. control system The equipment used to adjust some parameter of an ongoing process to regulate its behavior to a desired goal, such as positioning a disk drive head or regulating temperature of a furnace. control theory The mathematical study of behavior of control systems. controllability In control theory, the degree to which a system can be put into any desired state given manipulation of one variable. controller A system that adjusts some variable to control a process. copper cable certification The process of testing a computer network cable installation to verify that it meets standards. copper loss That portion of an electric machine or transformer's loss attributed to the resistance of conductors (which are not necessarily made


id: glossary-of-electrical-and-electronics-engineering-20260505-4
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-4.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
discrete-time signal A signal represented as a time series of samples taken at regular intervals. displacement current The effect of a time-varying electric field, which induces a magnetic field just as the motion of electrical charges does. display device Any device that displays data from an information system, such as a watch readout or an automatic scoreboard. dissipation The loss of energy in a system, such as dielectric loss in a capacitor. dissolved gas analysis A technique for fault detection in oil-filled transformers. distributed control system A control system in which significant parts of the control process are decentralized. distributed-element model An analysis of an electric circuit where capacitance, inductance, and resistance are distributed along the circuit, as in a transmission line, not concentrated in lumped components. distributed generation An electrical grid where multiple small sources contribute energy, instead of relatively few large central generating stations. distribution board A piece of electrical switchgear which distributes electric power to multiple branch circuits. distribution transformer A power transformer, usually used to change the utility distribution voltage to a lower voltage for use on the customer premises. Dolby A trademark for a noise reduction technique for analog sound recordings. dot convention A system


id: glossary-of-electrical-and-electronics-engineering-20260505-5
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-5.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
electrical grid A geographically distributed system to connect sources and users of electric power. electrical impedance That property of a circuit that resists the passage of electric current, usually in the context of alternating current. electrical insulation paper A grade of paper used for insulation of transformers, electrical machines, capacitors, and some cables. electrical insulation A material that resists electrical current flow. electrical load A consumer of electrical energy, turning it into light, heat, mechanical power, data, or chemical changes. electrical machine Any apparatus that converts between electrical power and mechanical power, such as a motor or generator. electrical measurements That branch of metrology concerned with electrical quantities. electrical network A network of electrical components and conductors. electrical polarity Identification of electrical terminals where current is flowing in the same direction relative to the device. electrical steel Any of several types of steel used for manufacturing the magnetic field components of machines and transformers. electrical substation A facility connecting a distribution network to a transmission network, usually with one or more transformers. electrical technologist A specialist in applying electrical theory and technique to practical problems. electrical wiring regulations The legal framework for electrical installations in buildings. electrical wiring The installation


id: glossary-of-electrical-and-electronics-engineering-20260505-6
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-6.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
equivalent impedance transforms A mathematical method to determine values of an equivalent circuit. error correction and detection Techniques used to improve reliability of computer memory or communications channels by including extra information along with the desired data. exponential stability A system that settles to a steady state after a disturbance, at a rate proportional to exponential time. extended Kalman filter A strategy for estimating an unknown value in a non-linear system by combining multiple measurements. == F == farad The SI unit of capacitance. Faraday shield A solid conductive shield around a volume, which blocks electromagnetic fields. Faraday–Lenz law One of Maxwell's equations, describing the relation between a changing magnetic field and production of an electromotive force. Faraday's law of induction The relation between a changing magnetic field and the resulting voltage produced in a closed path. fast Fourier transform A digital algorithm to analyze a time series of sampled data into a set of sine and cosine frequency components. fault A short circuit, open circuit, or other disruption of a power system. fax Also facsimile. The transmission of paper images by radio or by wire. feed forward A control system that adjusts the controlled variable based on a model


id: glossary-of-electrical-and-electronics-engineering-20260505-7
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-7.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
generator In circuit theory, an ideal voltage source or an ideal current source, whose properties are independent of the connected circuit. governor A speed regulator for a machine such as a steam engine; an early important feedback control cybernetic system. grid energy storage Any system tied to an electrical grid that stores electrical energy at low demand times and releases it to meet peak loads; it might be a centralized station like a pumped-storage hydroelectric plant, or might be distributed over many customer sites such as by the use of electric vehicle batteries. grid-tie inverter A power inverter that allows synchronization with the electrical grid for export of energy surplus to the facility's needs. ground A reference point for electrical potential; often connected to the Earth. ground and neutral Protective and circuit return conductors in a wiring system. ground fault circuit interrupter (GFCI) See residual-current device. ground-level power supply A system for providing powers for electric trams without overhead wires and without a permanently energized third rail. growler A test instrument that is used to diagnose some faults with AC motors. GSM The second generation of cellular mobile phone technology, deployed since 1991 in Europe. Gunn diode A two-terminal solid-state


id: glossary-of-electrical-and-electronics-engineering-20260505-8
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-8.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
image processing Electronic recording, storage, alteration, and reproduction of pictures. impulse response The response of a network to a sudden narrow pulse input. incandescent light bulb A device that uses a fine wire filament heated by an electric current to produce visible light (with heat usually produced as a byproduct). induction coil An early name for a transformer; or a type of transformer intended for high-voltage uses. induction cooker A cooking appliance that heats pots with magnetic fields by electromagnetic induction. induction generator A type of generator where the rotating field winding is excited by induction from the stationary armature winding. induction motor A type of motor where the rotating field winding is excited by induction from the stationary armature winding. induction regulator A type of variable transformer that provides stepless control of the output by changing the coupling between two coils. inductive coupling The transfer of energy between two circuits through a shared magnetic field passing through both. inductive output tube A high-power, high-frequency amplifier tube, in some forms capable of megawatt pulses at hundreds of megahertz. inductor Also coil, choke, or reactor. A passive two-terminal circuit component with a concentrated inductance, usually an insulated wire wound into a


id: glossary-of-electrical-and-electronics-engineering-20260505-9
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-9.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
Laplace transform A mathematical operation for solution of differential equations by transforming them to the s domain from the time domain. laser diode A semiconductor device that produces coherent laser radiation when properly energized. leakage inductance The inductance of a transformer that results from magnetic flux not linked by both primary and secondary windings. light-emitting diode (LED) A semiconductor device that produces visible, infrared, or ultraviolet light radiation when properly energized. linear alternator An electrical machine that generates electric power from the relative straight-line motion of its parts. linear motor An electrical machine that generates electric force in a straight line by the interaction of its moving parts and magnetic fields. linear variable differential transformer A transducer that produces an electrical signal proportional to the movement between its parts. lineman A specialist technician who installs outdoor plant wiring such as overhead circuits and power transmission lines. Litz wire A kind of stranded wire used to minimize losses in coils. load flow study A mathematical prediction of the flow of electric power in a network, based on a model of the actual or proposed system; necessary for planning of electrical grids. load following power plant A power plant that can economically


id: glossary-of-electrical-and-electronics-engineering-20260505-10
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-10.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
maximum prospective short-circuit current The calculated value of current that could flow if a short circuit occurred; a parameter for selection of circuit protection devices. Maxwell's equations The fundamental relations between electric and magnetic fields, expressed in concise mathematical form. mechanical rectifier An electromechanical device for converting alternating current to direct current, using sets of contacts which operate in synchronism with the AC. mechatronics Combinations of mechanical systems with electronics for sensing and control. memristor A hypothetical non-linear passive two-terminal electrical component relating electric charge and magnetic flux linkage. mercury-arc rectifier A mercury-arc valve; a vacuum tube device that converts alternating current to direct current by an arc in mercury vapor; displaced by solid-state devices, but formerly much used especially in high-voltage direct current transmission. mercury vapor lamp A lamp that generates light from a discharge struck in mercury vapor; formerly widely used in outdoor lighting, now replaced by lamps with better efficacy. mesh analysis A strategy for solution of the voltage distribution in some types of electrical networks. mesh networking A topology where infrastructure nodes connect to other nodes such as to convey information. Metadyne A DC electric machine with crossed fields and two sets of brushes, used as


id: glossary-of-electrical-and-electronics-engineering-20260505-11
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-11.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
nameplate capacityThe design power output of a generator, at specified temperature rise. nanoinverterGrid tied inverters rated less than 100 watts, useful for connection of single solar PV panels to a building AC power system. nanotechnologyTechnology that uses devices whose principal dimensions are of the order of a few nanometres. National Electrical CodeThe United States national technical standard for building wiring installation. National Electrical Manufacturers Association (NEMA)A US trade association for electrical manufacturers that also develops technical standards. negative feedbackFeedback from a control system output that tends to oppose the input. negative resistanceA voltage/current characteristic where increasing current leads to decreased voltage drop across the device. negawatt powerIn power grid demand management, that portion of load that can be met by conservation efforts or improved energy efficiency. neon signStrictly, a sign that glows orange because of a discharge through neon gas; less pedantically, any gas discharge tube formed into a sign. neon-sign transformerA high-voltage transformer with features intended to support operation of a neon sign. net meteringA metering plan that allows grid customers with their own generation to be billed only for their net import of energy from the grid. network analyzerAn analog computer system for modelling power grids; displaced now


id: glossary-of-electrical-and-electronics-engineering-20260505-12
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-12.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
pentagrid converter A type of self-oscillating vacuum tube used a frequency mixer in superheterodyne receivers. pentodeAny five-electrode electron device, but usually a kind of vacuum tube. permanent magnet synchronous generatorAn AC generator that uses a permanent field magnet instead of an electromagnet. permanent magnetA magnet that retains its polarization after an external field is removed. permeabilityThe amount of magnetisation in a material resulting from an applied magnetic field. phase converter Any electrical apparatus that converts power from one system of phases to another system, e.g. the conversion of single-phase power to three-phase. phase-fired controllers An AC power controller that adjusts the effective value of output by switching on at a variable time phase in the AC cycle. phase locked loop An oscillator circuit that produces an output signal that is in a fixed timing relation to a reference input. phase modulationImpressing information on a carrier wave by advancing or delaying the waveform slightly; related to frequency modulation. phasorA vector representing a signal of a given frequency in phase space. phasor measurement unitA system that measures the timing and amplitude of voltages and currents on an electrical grid, synchronized over a wide geographic area; the resulting measurements can be used to


id: glossary-of-electrical-and-electronics-engineering-20260505-13
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-13.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
power-line communicationThe impression of carrier waves on a power line circuit for signalling purposes. power MOSFETA metal oxide semiconductor field effect transistor suitable for use in circuits handling more than a watt of power. power plantA facility that converts other energy forms into electric power. power ratingThe nominal power that an apparatus or machine can handle, with specified or customary temperature rise and life expectancy. power qualityConformance of an electrical power supply with its specifications. power storageA facility that changes electric power into some form that can be stored and usefully reconverted back to electric power, for example, pumped storage or battery systems. power supplyA subsystem of a computer or other electronic device that turns electric power from a wall plug or batteries into a form suitable for use by the system. power-system automationThe implementation of power-operated switching and control that allows automatic operation of power system elements, instead of manual operation. power-system protectionThe technology of limiting the spread of failures of a power system to a minimum, and of preventing permanent damage to apparatus or conductors by such faults. printed circuit boardAn etched wiring assembly for interconnection of electronic components. printerA device that makes permanent human readable images and


id: glossary-of-electrical-and-electronics-engineering-20260505-14
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-14.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
recursive least squares filterAn algorithm for a digital filter system. Reed switchAn electrical switch made of two thin strips of ferromagnetic metal, which touch when subject to a magnetic field. regenerative brakingA braking scheme that returns energy to the source. regenerative circuitA circuit that employs positive feedback; can be an amplifier or an oscillator. relaxation oscillatorAn oscillator that relies on an active device periodically changing state; such oscillators usually produce a square-wave or sawtooth waveform, different from the approximately sinusoidal waveshape of a harmonic oscillator. relayAn electrically operated switch. reluctance motorA type of electric motor that induces non-permanent magnetic poles on the ferromagnetic rotor, relying on varying magnetic reluctance; the rotor carries no windings. remanenceThat portion of the applied magnetic field that the material retains when the external field is removed. remote racking systemA system for inserting circuit breakers into switchgear that allows the operator to stay at a safe distance from any possible arc hazard. remote sensingAcquisition of measurements of an object without contact, for example, measuring soil moisture by radar from an aircraft. renewable electricityElectric power derived from primary energy sources that replenish on a rapid scale or that are not appreciably diminished by human exploitation. renewable energy


id: glossary-of-electrical-and-electronics-engineering-20260505-15
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-15.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
Sallen–Key filterA family of active filters with a second-order characteristic, first described in 1955. sample and holdA circuit that takes a sample of a changing analog value and holds onto it until the value can be processed by some other stage. samplingThe process of taking a continually varying signal and turning it into a stream of numbers taken at regular intervals. sampling frequencyThe rate at which an analog value is sampled. satelliteA natural or artificial object that circles another, bound only by gravity. satellite radioA radio broadcasting service using signals from an Earth satellite to customer receivers. saturationThat point in the magnetization of a substance where most magnetic domains are aligned with the external field; further increase of the magnetizing force (H) gives only small increase in the magnetization (B). SCADASupervisory Control and Data Acquisition, management of geographically distributed automation systems such as for an electrical grid. scattering parametersA matrix that describes the electrical behavior of linear electrical networks, most prominently the distributed microwave systems. Schmitt triggerA circuit that behaves like a snap-action switch, suddenly changing state as an analog signal increases; displays hysteresis. Schottky diodeA diode that relies on the junction between a semiconductor and a metal. Scott-T transformerA


id: glossary-of-electrical-and-electronics-engineering-20260505-16
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-16.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
split phase distributionA type of distribution system that uses a center tapped transformer to provide two voltages to a building wiring system. split phase motorA type of single phase motor that uses a resistor, inductor, or capacitor and two windings to obtain a rotating magnetic field. square waveA waveform that spends equal times at the positive and negative peak values with rapid transitions between them. stability theoryThe systematic study of control systems that deals with their response to disturbances. stable polynomialThat class of polynomials representing the transfer functions of stable control systems. stacking factorA measure of the efficiency of filling the space of a machine core or winding; the proportion of active material in any given unit cross section. standing wave ratioA measure of impedance mismatch for transmission lines in microwave engineering; the ratio of peak amplitude of a standing wave to its minimum. star-mesh transformA mathematical technique used in circuit analysis. state observerIn control theory, that which discovers and reports the internal state of a controlled system. state space representationA mathematical technique to represent the internal state of a controlled system as a vector in a Euclidean space. static VAR compensatorA system that adjusts reactive power flow without moving


id: glossary-of-electrical-and-electronics-engineering-20260505-17
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-17.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
== T == tachometerAn instrument that measures rotational speed (or angular velocity). tapA connection to a winding at some point between the ends, used to adjust voltage. tap changerA switch that selects which transformer tap is connected to an external circuit; may be manually operated, or power operated; some types can be operated under load for voltage regulation purposes. technical drawingDrawings intended to convey information for construction, operation or maintenance of a system or equipment. telecommunicationThe field that deals with transmission of information over distances longer than can be covered by an unaided human. Telecommunications Industry AssociationA US based trade association that develops technical standards. telegraphA system for transmitting text messages, by wire or other means. telegrapher's equationsCoupled linear partial differential equations that relate the voltage and current on a transmission line. telephone balance unitA balun, a transformer used to convert between balanced and unbalanced lines, as used in telephone circuits. telephone lineOutside plant that connects a central office to subscriber equipment. telephoneTransmission of voice by electrical means. televisionTransmission of moving images by electrical means. Tellegen's theoremA theorem relating to branch currents in an electrical network. teslaThe SI unit of magnetic flux density. Tesla coilA kind of resonant transformer capable


id: glossary-of-electrical-and-electronics-engineering-20260505-18
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-18.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
ubiquitous computing A scenario where computer science is made to appear everywhere. ultrasonic motor A motor that relies on a component oscillating at an ultrasonic frequency. ultrasonics Term for the field of study pertaining to pressure oscillations in air or other media that are above the range of human hearing. ultrasound Sound having a frequency above the range of normal human hearing. A portmanteau of the former description of 'ultrasonic sound' undersampling Sampling a signal at less than the Nyquist rate; can produce alias frequencies or other artifacts. unijunction transistor A three terminal semiconductor device with a definite switching characteristic and only one PN junction. unshielded twisted pair Two wires wrapped around each other, but without a conductive cover. upsampling Sampling at greater than the Nyquist rate, which makes filter design easier. utility frequency 60 or 50 cycles per second, used for electric power. utility pole A columnar structure that carries wires for electrical power distribution, cable television, telephone or similar services. == V == vacuum capacitor A capacitor using vacuum as its dielectric; useful at high voltages or radio frequency. vacuum tube An electron device that relies on flow of electrons through a vacuum or low-pressure gas; a valve.


id: glossary-of-electrical-and-electronics-engineering-20260505-19
file: data/en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering-19.md
category: reference
title: Glossary of electrical and electronics engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_electrical_and_electronics_engineering
date_saved: 2026-05-05T07:50:45.907292+00:00
instance: kb-cron
parent: glossary-of-electrical-and-electronics-engineering-20260505-0
summary:
war of the currents The late 19th century commercial dispute on whether AC or DC was the best system for power distribution. Ward Leonard control A speed control system for DC machines using an interconnected generator and motor. watt The SI unit of power, work done per unit time. wattmeter An instrument that measures electrical power. waveguide A tubular structure that guides electromagnetic waves, much used at microwave frequencies; an optical fiber is a kind of optical waveguide. weber The SI unit of magnetic flux. wet transformer In telephone systems, a matching transformer that can operate while carrying a substantial DC "wetting" current. Wien bridge oscillator A type of electronic oscillator that generates sine waves and is based on a bridge circuit. Wiener filter A class of filters used in signal processing, used to fit an estimate to noisy signal data. Williams tube A cathode ray vacuum tube used as an early form of computer memory. wind farm An array of two or more wind turbines, usually sharing a substation. wind power Generation of electricity (sometimes mechanical power) from wind. wind turbine A rotating machine that extracts energy from wind. wire A strand of metal much, much, longer than it


id: glossary-of-engineering-a-l-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_A–L-0.md
category: reference
title: Glossary of engineering: A–L
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_A–L
date_saved: 2026-05-05T07:50:47.362460+00:00
instance: kb-cron
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This glossary of engineering terms is a list of definitions about the major concepts of engineering. Please see the bottom of the page for glossaries of specific fields of engineering. == A == Absolute electrode potentialIn electrochemistry, according to an IUPAC definition, is the electrode potential of a metal measured with respect to a universal reference system (without any additional metal–solution interface). Absolute pressureis zero-referenced against a perfect vacuum, using an absolute scale, so it is equal to gauge pressure plus atmospheric pressure. Absolute zeroThe lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as 0. Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. The theoretical temperature is determined by extrapolating the ideal gas law; by international agreement, absolute zero is taken as −273.15° on the Celsius scale (International System of Units), which equals −459.67° on the Fahrenheit scale (United States customary units or Imperial units). The corresponding Kelvin and Rankine temperature scales set their zero points at absolute zero by definition. AbsorbanceAbsorbance or decadic absorbance is the


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Afocal systemAn optical system that produces no net convergence or divergence of the beam, i.e. has an infinite effective focal length. Agricultural engineeringThe profession of designing machinery, processes, and systems for use in agriculture. AlbedoA measure of the fraction of light reflected from an astronomical body or other object. AlkaneAn alkane, or paraffin (a historical name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. AlkeneAn unsaturated hydrocarbon that contains at least one carbon–carbon double bond. The words alkene and olefin are often used interchangeably. Alkyneis an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical formula CnH2n−2. Alloyis a combination of metals or of a metal and another element. Alloys are defined by a metallic bonding character. Alpha particleAlpha particles consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be produced


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It was formulated by Archimedes of Syracuse Area moment of inertiaThe 2nd moment of area, also known as moment of inertia of plane area, area moment of inertia, or second area moment, is a geometrical property of an area which reflects how its points are distributed with regard to an arbitrary axis. The second moment of area is typically denoted with either an I {\displaystyle I} for an axis that lies in the plane or with a J {\displaystyle J} for an axis perpendicular to the plane. In both cases, it is calculated with a multiple integral over the object in question. Its dimension is L (length) to the fourth power. Its unit of dimension when working with the International System of Units is meters to the fourth power, m4. Arithmetic meanIn mathematics and statistics, the arithmetic mean or simply the mean or average when the context is clear, is the sum of a collection of numbers divided by the number of numbers in the collection. Arithmetic progressionIn mathematics, an arithmetic progression (AP) or arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant. Difference here means the second minus the first. For


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== B == BarometerA device for measuring pressure. BatteryElectrochemical cells that transform chemical energy into electricity. BaseIn chemistry, bases are substances that, in aqueous solution, release hydroxide (OH−) ions, are slippery to the touch, can taste bitter if an alkali, change the color of indicators (e.g., turn red litmus paper blue), react with acids to form salts, promote certain chemical reactions (base catalysis), accept protons from any proton donor, and/or contain completely or partially displaceable OH− ions. BaudRate at which data is transferred in symbols/second; a symbol may represent one or more bits. BeamA structural element whose length is significantly greater than its width or height. Beer–Lambert lawThe Beer–Lambert law, also known as Beer's law, the Lambert–Beer law, or the Beer–Lambert–Bouguer law relates the attenuation of light to the properties of the material through which the light is travelling. The law is commonly applied to chemical analysis measurements and used in understanding attenuation in physical optics, for photons, neutrons, or rarefied gases. In mathematical physics, this law arises as a solution of the BGK equation. BeltA closed loop of flexible material used to transmit mechanical power from one pulley to another. Belt frictionDescribes the friction forces between a belt and


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Binomial distributionIn probability theory and statistics, the binomial distribution with parameters n and p is the discrete probability distribution of the number of successes in a sequence of n independent experiments, each asking a yes–no question, and each with its own boolean-valued outcome: a random variable containing a single bit of information: success/yes/true/one (with probability p) or failure/no/false/zero (with probability q=1 − p). A single success-failure experiment is also called a Bernoulli trial or Bernoulli experiment and a sequence of outcomes is called a Bernoulli process; for a single trial, i.e., n=1, the binomial distribution is a Bernoulli distribution. The binomial distribution is the basis for the popular binomial test of statistical significance. BiocatalysisBiocatalysis refers to the use of living (biological) systems or their parts to speed up (catalyze) chemical reactions. In biocatalytic processes, natural catalysts, such as enzymes, perform chemical transformations on organic compounds. Both enzymes that have been more or less isolated and enzymes still residing inside living cells are employed for this task. The modern usage of biotechnologically produced and possibly modified enzymes for organic synthesis is termed chemoenzymatic synthesis; the reactions performed are chemoenzymatic reactions. Biomedical engineeringBiomedical engineering (BME) or medical engineering is the application of


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where ni are any integers and ai are known as the primitive vectors which lie in different directions (not necessarily mutually perpendicular) and span the lattice. This discrete set of vectors must be closed under vector addition and subtraction. For any choice of position vector R, the lattice looks exactly the same. Brayton cycleA thermodynamic cycle model for an ideal heat engine, in which heat is added or removed at constant pressure; approximated by a gas turbine. Break-evenThe break-even point (BEP) in economics, business—and specifically cost accounting—is the point at which total cost and total revenue are equal, i.e. "even". There is no net loss or gain, and one has "broken even", though opportunity costs have been paid and capital has received the risk-adjusted, expected return. In short, all costs that must be paid are paid, and there is neither profit nor loss. Brewster's angleBrewster's angle (also known as the polarization angle) is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection. When unpolarized light is incident at this angle, the light that is reflected from the surface is therefore perfectly polarized. This special angle of incidence


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CalculusThe mathematics of change. CapacitanceThe ability of a body to store electrical charge. Capacitive reactanceThe impedance of a capacitor in an alternating current circuit, the opposition to current flow. CapacitorAn electrical component that stores energy in an electric field. Capillary actionCapillary action (sometimes capillarity, capillary motion, capillary effect, or wicking) is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. The effect can be seen in the drawing up of liquids between the hairs of a paintbrush, in a thin tube, in porous materials such as paper and plaster, in some non-porous materials such as sand and liquefied carbon fiber, or in a cell. It occurs because of intermolecular forces between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and adhesive forces between the liquid and container wall act to propel the liquid. CarbonateAny mineral with bound carbon dioxide. Carnot cycleA hypothetical thermodynamic cycle for a heat engine; no thermodynamic cycle can be more efficient than a Carnot cycle operating between the same two temperature


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Chain reactionis a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events. Change of base rule. Charles's lawCharles's law (also known as the law of volumes) is an experimental gas law that describes how gases tend to expand when heated. A modern statement of Charles's law is: When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion. Chemical bondis a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, ionic and metallic bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the London dispersion force and hydrogen bonding. Chemical compoundis a chemical substance composed of many identical molecules (or molecular entities) composed of atoms from more than one element held together by chemical bonds. A


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for an infinitesimal change in entropy S applies not only to cyclic processes, but to any process that occurs in a closed system. Coefficient of performanceThe coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work required. Higher COPs equate to lower operating costs. The COP usually exceeds 1, especially in heat pumps, because, instead of just converting work to heat (which, if 100% efficient, would be a COP_hp of 1), it pumps additional heat from a heat source to where the heat is required. For complete systems, COP calculations should include energy consumption of all power consuming auxiliaries. COP is highly dependent on operating conditions, especially absolute temperature and relative temperature between sink and system, and is often graphed or averaged against expected conditions. Coefficient of variationIn probability theory and statistics, the coefficient of variation (CV), also known as relative standard deviation (RSD), is a standardized measure of dispersion of a probability distribution or frequency distribution. It is often expressed as a percentage, and is defined as the ratio of the standard deviation σ {\displaystyle \ \sigma } to the


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On the other hand, a conjugate base is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the removal of a proton from an acid. Because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic. Conjugate baseA conjugate acid, within the Brønsted–Lowry acid–base theory, is a species formed by the reception of a proton (H+) by a base—in other words, it is a base with a hydrogen ion added to it. On the other hand, a conjugate base is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the removal of a proton from an acid. Because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic. Conservation of energyIn physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. This law means that energy can neither be created nor destroyed; rather, it can only


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1 C = 1 A ⋅ 1 s {\displaystyle 1~{\text{C}}=1~{\text{A}}\cdot 1~{\text{s}}} Thus, it is also the amount of excess charge on a capacitor of one farad charged to a potential difference of one volt: 1 C = 1 F ⋅ 1 V {\displaystyle 1~{\text{C}}=1~{\text{F}}\cdot 1~{\text{V}}} The coulomb is equivalent to the charge of approximately 6.242×1018 (1.036×10−5 mol) protons, and −1 C is equivalent to the charge of approximately 6.242×1018 electrons. A new definition, in terms of the elementary charge, will take effect on 20 May 2019. The new definition defines the elementary charge (the charge of the proton) as exactly 1.602176634×10−19 coulombs. This would implicitly define the coulomb as 1⁄0.1602176634×1018 elementary charges. Coulomb's lawCoulomb's law, or Coulomb's inverse-square law, is a law of physics for quantifying Coulomb's force, or electrostatic force. Electrostatic force is the amount of force with which stationary, electrically charged particles either repel, or attract each other. This force and the law for quantifying it, represent one of the most basic forms of force used in the physical sciences, and were an essential basis to the study and development of the theory and field of classical electromagnetism. The law was first published in 1785 by French physicist


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A deformation may be caused by external loads, body forces (such as gravity or electromagnetic forces), or changes in temperature, moisture content, or chemical reactions, etc. Degrees of freedomThe number of parameters required to define the motion of a dynamical system. Delta robotA tripod linkage, used to construct fast-acting manipulators with a wide range of movement. Delta-wye transformerA type of transformer used in three-phase power systems. De Moivre–Laplace theoremIn probability theory, the de Moivre–Laplace theorem, which is a special case of the central limit theorem, states that the normal distribution may be used as an approximation to the binomial distribution under certain conditions. In particular, the theorem shows that the probability mass function of the random number of "successes" observed in a series of n {\displaystyle n} independent Bernoulli trials, each having probability p {\displaystyle p} of success (a binomial distribution with n {\displaystyle n} trials), converges to the probability density function of the normal distribution with mean n p {\displaystyle np} and standard deviation n p ( 1 − p ) {\displaystyle {\sqrt {np(1-p)}}} , as n {\displaystyle n} grows large, assuming p {\displaystyle p} is not 0 {\displaystyle 0} or 1 {\displaystyle 1} . DensityThe density, or more


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ν ( x ) = ∫ θ ( x ) d x {\displaystyle \nu (x)=\int \theta (x)dx} . DispersionIn optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Media having this common property may be termed dispersive media. Sometimes the term chromatic dispersion is used for specificity. Although the term is used in the field of optics to describe light and other electromagnetic waves, dispersion in the same sense can apply to any sort of wave motion such as acoustic dispersion in the case of sound and seismic waves, in gravity waves (ocean waves), and for telecommunication signals along transmission lines (such as coaxial cable) or optical fiber. Displacement (fluid)In fluid mechanics, displacement occurs when an object is immersed in a fluid, pushing it out of the way and taking its place. The volume of the fluid displaced can then be measured, and from this, the volume of the immersed object can be deduced (the volume of the immersed object will be exactly equal to the volume of the displaced fluid). Displacement (vector)is a vector whose length is the shortest distance from the initial to the final position of a point P.


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The SI unit for measuring an electric current is the ampere, which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current is measured using a device called an ammeter. Electric displacement fieldIn physics, the electric displacement field, denoted by D, is a vector field that appears in Maxwell's equations. It accounts for the effects of free and bound charge within materials. D stands for "displacement", as in the related concept of displacement current in dielectrics. In free space, the electric displacement field is equivalent to flux density, a concept that lends understanding to Gauss's law. In the International System of Units (SI), it is expressed in units of coulomb per meter squared (C⋅m−2). Electric generatorIn electricity generation, a generator, also called electric generator, electrical generator, and electromagnetic generator is a device that converts motive power (mechanical energy) into electrical power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines and even hand cranks. Electric fieldsurrounds an electric charge, and exerts force on other charges in the field, attracting or repelling them. Electric field is sometimes abbreviated as E-field. Electric


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Its quantum counterpart is one of the four fundamental forces of nature (the others are gravitation, weak interaction and strong interaction.) Electromagnetic radiationIn physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space, carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays. ElectromechanicsElectromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems interact with each other. This process is especially prominent in systems such as those of DC or AC rotating electrical machines which can be designed and operated to generate power from a mechanical process (generator) or used to power a mechanical effect (motor). Electrical engineering in this context also encompasses electronics engineering. Electronis a subatomic particle, symbol e− or β−, whose electric charge is negative one elementary charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron has a mass that is approximately 1/1836 that of the


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Environmental engineeringIs a job type that is a professional engineering discipline and takes from broad scientific topics like chemistry, biology, ecology, geology, hydraulics, hydrology, microbiology, and mathematics to create solutions that will protect and also improve the health of living organisms and improve the quality of the environment. Environmental engineering is a sub-discipline of civil engineering and chemical engineering. Engineering physicsOr engineering science, refers to the study of the combined disciplines of physics, mathematics, chemistry, biology, and engineering, particularly computer, nuclear, electrical, electronic, aerospace, materials or mechanical engineering. By focusing on the scientific method as a rigorous basis, it seeks ways to apply, design, and develop new solutions in engineering. EnzymeEnzymes are proteins that act as biological catalysts (biocatalysts). Catalysts accelerate chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Escape velocityThe minimum velocity at which an object can escape a gravitation field. EstimatorIn statistics, an estimator is a rule for calculating an estimate of a given quantity based on observed data: thus the


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NA = 6.02214076×1023 mol−1. Both of these values have exact defined values, and hence F has a known exact value. NA is the Avogadro constant (the ratio of the number of particles, N, which is unitless, to the amount of substance, n, in units of moles), and e is the elementary charge or the magnitude of the charge of an electron. This relation holds because the amount of charge of a mole of electrons is equal to the amount of charge in one electron multiplied by the number of electrons in a mole. Fermat's principleIn optics, Fermat's principle, or the principle of least time, named after French mathematician Pierre de Fermat, is the principle that the path taken between two points by a ray of light is the path that can be traversed in the least time. This principle is sometimes taken as the definition of a ray of light. However, this version of the principle is not general; a more modern statement of the principle is that rays of light traverse the path of stationary optical length with respect to variations of the path. In other words, a ray of light prefers the path such that there are other


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The lines were originally observed as dark features (absorption lines) in the optical spectrum of the Sun. Free fallIn Newtonian physics, free fall is any motion of a body where gravity is the only force acting upon it. In the context of general relativity, where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it. Frequency modulationFrequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and computing. Freezing pointThe melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 kPa.


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When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point or crystallization point. Because of the ability of substances to supercool, the freezing point can easily appear to be below its actual value. When the "characteristic freezing point" of a substance is determined, in fact the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice, that is, the melting point. FrictionIs the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into static friction ("stiction") between non-moving surfaces, and kinetic friction between moving surfaces. With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as asperities (see Figure 1). Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces. Skin friction is a


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Galvanic cellA galvanic cell or voltaic cell, named after Luigi Galvani or Alessandro Volta, respectively, is an electrochemical cell that derives electrical energy from spontaneous redox reactions taking place within the cell. It generally consists of two different metals immersed in electrolytes, or of individual half-cells with different metals and their ions in solution connected by a salt bridge or separated by a porous membrane. Volta was the inventor of the voltaic pile, the first electrical battery. In common usage, the word "battery" has come to include a single galvanic cell, but a battery properly consists of multiple cells. Gamma raysA gamma ray, or gamma radiation (symbol γ or γ {\displaystyle \gamma } ), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and so imparts the highest photon energy. GasIs one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). A gas


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title: Glossary of engineering: A–L
tags: science, encyclopedia
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Rate 1 Rate 2 = M 2 M 1 {\displaystyle {{\mbox{Rate}}_{1} \over {\mbox{Rate}}_{2}}={\sqrt {M_{2} \over M_{1}}}} , where: Rate1 is the rate of effusion for the first gas. (volume or number of moles per unit time). Rate2 is the rate of effusion for the second gas. M1 is the molar mass of gas 1 M2 is the molar mass of gas 2. Gravitational constantThe gravitational constant (also known as the universal gravitational constant, the Newtonian constant of gravitation, or the Cavendish gravitational constant), denoted by the letter G, is an empirical physical constant involved in the calculation of gravitational effects in Sir Isaac Newton's law of universal gravitation and in Albert Einstein's general theory of relativity. Gravitational energyGravitational energy or gravitational potential energy is the potential energy a massive object has in relation to another massive object due to gravity. It is the potential energy associated with the gravitational field, which is released (converted into kinetic energy) when the objects fall towards each other. Gravitational potential energy increases when two objects are brought further apart. For two pairwise interacting point particles, the gravitational potential energy U {\displaystyle U} is given by U = − G M m R , {\displaystyle


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_A–L-21.md
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title: Glossary of engineering: A–L
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Half-lifeThe period at which one-half of a quantity of an unstable isotope has decayed into other elements; the time at which half of a substance has diffused out of or otherwise reacted in a system. HapticTactile feedback technology using the operator's sense of touch. Also sometimes applied to robot manipulators with their own touch sensitivity. HardnessIs a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. Some materials (e.g. metals) are harder than others (e.g. plastics, wood). Macroscopic hardness is generally characterized by strong intermolecular bonds, but the behavior of solid materials under force is complex; therefore, there are different measurements of hardness: scratch hardness, indentation hardness, and rebound hardness. Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Harmonic meanIn mathematics, the harmonic mean (sometimes called the subcontrary mean) is one of several kinds of average, and in particular, one of the Pythagorean means. Typically, it is appropriate for situations when the average of rates is desired. The harmonic mean can be expressed as the reciprocal of the arithmetic mean of the reciprocals of the given set of observations. As a simple example, the harmonic mean of 1,


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_A–L-22.md
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title: Glossary of engineering: A–L
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where P {\displaystyle P} , V {\displaystyle V} and T {\displaystyle T} are the pressure, volume and temperature; n {\displaystyle n} is the amount of substance; and R {\displaystyle R} is the ideal gas constant. It is the same for all gases. It can also be derived from the microscopic kinetic theory, as was achieved (apparently independently) by August Krönig in 1856 and Rudolf Clausius in 1857. IdentityIn mathematics, an identity is an equality relating one mathematical expression A to another mathematical expression B, such that A and B (which might contain some variables) produce the same value for all values of the variables within a certain range of validity. In other words, A = B is an identity if A and B define the same functions, and an identity is an equality between functions that are differently defined. For example, ( a + b ) 2 = a 2 + 2 a b + b 2 {\displaystyle (a+b)^{2}=a^{2}+2ab+b^{2}} and cos 2 ⁡ θ + sin 2 ⁡ θ = 1 {\displaystyle \cos ^{2}\theta +\sin ^{2}\theta =1} are identities. Identities are sometimes indicated by the triple bar symbol ≡ instead of =, the equals sign. Impedance (electrical)In electrical engineering, electrical


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title: Glossary of engineering: A–L
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Inorganic chemistryDeals with synthesis and behavior of inorganic and organometallic compounds. This field covers chemical compounds that are not carbon-based, which are the subjects of organic chemistry. The distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the chemical industry, including catalysis, materials science, pigments, surfactants, coatings, medications, fuels, and agriculture.IonIs a particle, atom or molecule with a net electrical charge. The charge of the electron is considered negative by convention. The negative charge of an ion is equal and opposite to charged proton(s) considered positive by convention. The net charge of an ion is non-zero due to its total number of electrons being unequal to its total number of protons. Ionic bondingIs a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electronegativities, and is the primary interaction occurring in ionic compounds. It is one of the main types of bonding along with covalent bonding and metallic bonding. Ions are atoms (or groups of atoms) with an electrostatic charge. Atoms that gain electrons make negatively charged ions (called anions). Atoms


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title: Glossary of engineering: A–L
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== J == J/psi mesonThe J/ψ (J/psi) meson or psion is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium". The J/ψ is the most common form of charmonium, due to its spin of 1 and its low rest mass. The J/ψ has a rest mass of 3.0969 GeV/c2, just above that of the ηc (2.9836 GeV/c2), and a mean lifetime of 7.2×10−21 s. This lifetime was about a thousand times longer than expected. JouleThe SI unit of energy. The joule, (symbol: J), is a derived unit of energy in the International System of Units. It is equal to the energy transferred to (or work done on) an object when a force of one newton acts on that object in the direction of the object's motion through a distance of one metre (1 newton-metre or N⋅m). It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889). Joule heatingAlso known


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title: Glossary of engineering: A–L
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Lenz's law may be seen as analogous to Newton's third law in classical mechanics. LeptonIn particle physics, a lepton is an elementary particle of half-integer spin (spin 1⁄2) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons), and neutral leptons (better known as neutrinos). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium, while neutrinos rarely interact with anything, and are consequently rarely observed. The best known of all leptons is the electron. LeverIs a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is divided into three types. Also, leverage is mechanical advantage gained in a system. It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage. The ratio of the output force to the input force is the mechanical advantage of the lever. As such,


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log b ⁡ ( x ) = y {\displaystyle \log _{b}(x)=y\ } exactly if b y = x {\displaystyle \ b^{y}=x\ } and x > 0 {\displaystyle \ x>0} and b > 0 {\displaystyle \ b>0} and b ≠ 1 {\displaystyle \ b\neq 1} . For example, log2 64=6, as 26=64. The logarithm base 10 (that is b=10) is called the decimal or common logarithm and is commonly used in science and engineering. The natural logarithm has the number e (that is b ≈ 2.718) as its base; its use is widespread in mathematics and physics, because of its simpler integral and derivative. The binary logarithm uses base 2 (that is b=2) and is frequently used in computer science. Logarithms are examples of concave functions. Logarithmic identitiesSeveral important formulas, sometimes called logarithmic identities or log laws, relate logarithms to one another. Logarithmic mean temperature difference(Also known as log mean temperature difference, LMTD) is used to determine the temperature driving force for heat transfer in flow systems, most notably in heat exchangers. The LMTD is a logarithmic average of the temperature difference between the hot and cold feeds at each end of the double pipe exchanger. For a given heat exchanger


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-0.md
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title: Glossary of engineering: M–Z
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This glossary of engineering terms is a list of definitions about the major concepts of engineering. Please see the bottom of the page for glossaries of specific fields of engineering. == M == Macaulay's method(The double integration method) is a technique used in structural analysis to determine the deflection of Euler-Bernoulli beams. Use of Macaulay's technique is very convenient for cases of discontinuous and/or discrete loading. Typically partial uniformly distributed loads (u.d.l.) and uniformly varying loads (u.v.l.) over the span and a number of concentrated loads are conveniently handled using this technique. Mach numberThe ratio of the speed of an object to the speed of sound. MachineA machine (or mechanical device) is a mechanical structure that uses power to apply forces and control movement to perform an intended action. Machines can be driven by animals and people, by natural forces such as wind and water, and by chemical, thermal, or electrical power, and include a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement. They can also include computers and sensors that monitor performance and plan movement, often called mechanical systems. Machine codeIn computer programming, machine code, consisting of machine language


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In electromagnetics, the term "magnetic field" is used for two distinct but closely related vector fields denoted by the symbols B and H. In the International System of Units, H, magnetic field strength, is measured in the SI base units of ampere per meter (A/m). B, magnetic flux density, is measured in tesla (in SI base units: kilogram per second2 per ampere), which is equivalent to newton per meter per ampere. H and B differ in how they account for magnetization. In vacuum, the two fields are related through the vacuum permeability, B / μ 0 = H {\displaystyle \mathbf {B} /\mu _{0}=\mathbf {H} } ; but in a magnetized material, the terms differ by the material's magnetization at each point. Magnetismis a class of physical attributes that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. Magnetism is one aspect of the combined phenomenon of electromagnetism. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Demagnetizing a magnet is also possible. Only


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In mathematical terms, failure theory is expressed in the form of various failure criteria which are valid for specific materials. Failure criteria are functions in stress or strain space which separate "failed" states from "unfailed" states. A precise physical definition of a "failed" state is not easily quantified and several working definitions are in use in the engineering community. Quite often, phenomenological failure criteria of the same form are used to predict brittle failure and ductile yields. Material propertiesA material's property is an intensive property of some material, i.e., a physical property that does not depend on the amount of the material. These quantitative properties may be used as a metric by which the benefits of one material versus another can be compared, thereby aiding in materials selection. Materials scienceThe interdisciplinary field of materials science, also commonly termed materials science and engineering, covers the design and discovery of new materials, particularly solids. The intellectual origins of materials science stem from the Enlightenment, when researchers began to use analytical thinking from chemistry, physics, and engineering to understand ancient, phenomenological observations in metallurgy and mineralogy. Materials science still incorporates elements of physics, chemistry, and engineering. As such, the field was long considered


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Not all matrices are related to linear algebra. This is in particular the case, in graph theory, of incidence matrices and adjacency matrices. MatterIn classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both rest mass and volume. However it does not include massless particles such as photons, or other energy phenomena or waves such as light. Matter exists in various states (also known as phases). These include classical everyday phases such as solid, liquid, and gas – for example water exists as ice, liquid water, and gaseous steam – but other states are possible, including plasma, Bose–Einstein condensates, fermionic condensates, and quark–gluon plasma. Maximum-distortion energy theory. Maximum-normal-stress theory. Maximum shear stress. Maxwell's equationsare a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits.


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The central tendency of a distribution is typically contrasted with its dispersion or variability; dispersion and central tendency are the often characterized properties of distributions. Analysis may judge whether data has a strong or a weak central tendency based on its dispersion. Mechanical advantageis a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to obtain a desired amplification in the output force. The model for this is the law of the lever. Machine components designed to manage forces and movement in this way are called mechanisms. An ideal mechanism transmits power without adding to or subtracting from it. This means the ideal mechanism does not include a power source, is frictionless, and is constructed from rigid bodies that do not deflect or wear. The performance of a real system relative to this ideal is expressed in terms of efficiency factors that take into account departures from the ideal. Mechanical engineeringis an engineering branch that combines engineering physics and mathematics principles with materials science to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldest and broadest of the engineering branches. Mechanical filteris


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When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point or crystallization point. Because of the ability of substances to supercool, the freezing point can easily appear to be below its actual value. When the "characteristic freezing point" of a substance is determined, in fact the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice, that is, the melting point." MesonIn particle physics, mesons are hadronic subatomic particles composed of an equal number of quarks and antiquarks, usually one of each, bound together by strong interactions. Because mesons are composed of quark subparticles, they have a meaningful physical size, a diameter of roughly one femtometer (1×10−15 m), which is about 0.6 times the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Heavier mesons decay to lighter mesons and ultimately to stable electrons, neutrinos and photons. Metallic bondingis a type of chemical bonding that arises from the electrostatic attractive force between conduction electrons (in the form of an electron cloud of delocalized electrons) and positively charged metal ions.


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In particular, a family of lattice planes is determined by three integers h, k, and ℓ, the Miller indices. They are written (hkℓ), and denote the family of planes orthogonal to h b 1 + k b 2 + ℓ b 3 {\displaystyle h\mathbf {b_{1}} +k\mathbf {b_{2}} +\ell \mathbf {b_{3}} } , where b i {\displaystyle \mathbf {b_{i}} } are the basis of the reciprocal lattice vectors (note that the plane is not always orthogonal to the linear combination of direct lattice vectors h a 1 + k a 2 + ℓ a 3 {\displaystyle h\mathbf {a_{1}} +k\mathbf {a_{2}} +\ell \mathbf {a_{3}} } because the lattice vectors need not be mutually orthogonal). By convention, negative integers are written with a bar, as in 3 for −3. The integers are usually written in lowest terms, i.e. their greatest common divisor should be 1. Miller indices are also used to designate reflections in X-ray crystallography. In this case the integers are not necessarily in lowest terms, and can be thought of as corresponding to planes spaced such that the reflections from adjacent planes would have a phase difference of exactly one wavelength (2π), regardless of whether there are atoms on all these


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Molar concentrationMolar concentration (also called molarity, amount concentration or substance concentration) is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution. In chemistry, the most commonly used unit for molarity is the number of moles per liter, having the unit symbol mol/L or mol⋅dm−3 in SI unit. A solution with a concentration of 1 mol/L is said to be 1 molar, commonly designated as 1 M. To avoid confusion with SI prefix mega, which has the same abbreviation, small caps ᴍ or italicized M are also used in journals and textbooks. Molar massIn chemistry, the molar mass of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance in that sample, measured in moles. It is the mass of 1 mole of the substance or 6.022×1023 particles, expressed in grams. The molar mass is a bulk, not molecular, property of a substance. The molar mass is an average of many instances of the compound, which often vary in mass due to the presence of isotopes. Most commonly, the molar mass is


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Nanoengineeringis the practice of engineering on the nanoscale. It derives its name from the nanometre, a unit of measurement equalling one billionth of a meter. Nanoengineering is largely a synonym for nanotechnology, but emphasizes the engineering rather than the pure science aspects of the field. NanotechnologyThe technology of systems built with moving parts on the order of a nanometre in size. Navier–Stokes equationsIn physics, the Navier–Stokes equations are a set of partial differential equations which describe the motion of viscous fluid substances, named after French engineer and physicist Claude-Louis Navier and Anglo-Irish physicist and mathematician George Gabriel Stokes. NeutrinoA neutrino (denoted by the Greek letter ν) is a fermion (an elementary particle with spin of ⁠1/2⁠) that interacts only via the weak subatomic force and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The mass of the neutrino is much smaller than that of the other known elementary particles. The weak force has a very short range, the gravitational interaction is extremely weak, and neutrinos do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded


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A matrix representation of P (in any number of dimensions) has determinant equal to −1, and hence is distinct from a rotation, which has a determinant equal to 1. In a two-dimensional plane, a simultaneous flip of all coordinates in sign is not a parity transformation; it is the same as a 180°-rotation. In quantum mechanics, wave functions that are unchanged by a parity transformation are described as even functions, while those that change sign under a parity transformation are odd functions.fn=A hydrocarbon compound, solid at room temperature. Paramagnetismis a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, diamagnetic materials are repelled by magnetic fields and form induced magnetic fields in the direction opposite to that of the applied magnetic field. Paramagnetic materials include most chemical elements and some compounds; they have a relative magnetic permeability slightly greater than 1 (i.e., a small positive magnetic susceptibility) and hence are attracted to magnetic fields. The magnetic moment induced by the applied field is linear in the field strength and rather weak. It typically requires a


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F = C − P + 2. {\displaystyle F=C-P+2.} It was derived by American physicist Josiah Willard Gibbs in his landmark paper titled On the Equilibrium of Heterogeneous Substances, published in parts between 1875 and 1878. The rule assumes the components do not react with each other. Photonis a type of elementary particle. It is the quantum of the electromagnetic field including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always move at the speed of light in vacuum, 299792458 m/s (or about 186,282 mi/s). The photon belongs to the class of bosons. Physical chemistryis the study of macroscopic, and particulate phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics, analytical dynamics and chemical equilibrium. Physical quantityA physical quantity is a property of a material or system that can be quantified by measurement. A physical quantity can be expressed as a value, which is the algebraic multiplication of a numerical value and a unit. For example, the physical quantity mass can be quantified as n kg, where n is the numerical


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Electric power can be delivered over long distances by transmission lines and used for applications such as motion, light or heat with high efficiency. Power (physics)In physics, power is the amount of energy transferred or converted per unit time. In the International System of Units, the unit of power is the watt, equal to one joule per second. In older works, power is sometimes called activity. Power is a scalar quantity. Power factorIn electrical engineering, the power factor of an AC power system is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit, and is a dimensionless number in the closed interval of −1 to 1. A power factor of less than one indicates the voltage and current are not in phase, reducing the average product of the two. Real power is the instantaneous product of voltage and current and represents the capacity of the electricity for performing work. Apparent power is the product of RMS current and voltage. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source,


id: glossary-of-engineering-m-z-20260505-12
file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-12.md
category: reference
title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt. The drive element of a pulley system can be a rope, cable, belt, or chain. Pumpis a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they use to move the fluid: direct lift, displacement, and gravity pumps. Pumps operate by some mechanism (typically reciprocating or rotary), and consume energy to perform mechanical work moving the fluid. Pumps operate via many energy sources, including manual operation, electricity, engines, or wind power, and come in many sizes, from microscopic for use in medical applications, to large industrial pumps. == Q == Quantum electrodynamicsIn particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete


id: glossary-of-engineering-m-z-20260505-13
file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-13.md
category: reference
title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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RegelationThe phenomena of melting under pressure, then freezing when the pressure is reduced. Relative densityRelative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest (at 4 °C or 39.2 °F); for gases, the reference is air at room temperature (20 °C or 68 °F). The term "relative density" is often preferred in scientific usage. Relative velocityThe relative velocity v → B ∣ A {\displaystyle {\vec {v}}_{B\mid A}} (also v → B A {\displaystyle {\vec {v}}_{BA}} or v → B rel ⁡ A {\displaystyle {\vec {v}}_{B\operatorname {rel} A}} ) is the velocity of an object or observer B in the rest frame of another object or observer A. Reliability engineeringis a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specified period of time. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-14.md
category: reference
title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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In the case of robotically-assisted minimally-invasive surgery, instead of directly moving the instruments, the surgeon uses one of two methods to administer the instruments. These include using a direct telemanipulator or through computer control. A telemanipulator is a remote manipulator that allows the surgeon to perform the normal movements associated with the surgery. The robotic arms carry out those movements using end-effectors and manipulators to perform the actual surgery. In computer-controlled systems, the surgeon uses a computer to control the robotic arms and its end-effectors, though these systems can also still use telemanipulators for their input. One advantage of using the computerized method is that the surgeon does not have to be present, leading to the possibility for remote surgery. RoboticsIs an interdisciplinary field that integrates computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist humans. Robotics integrates fields of mechanical engineering, electrical engineering, information engineering, mechatronics, electronics, bioengineering, computer engineering, control engineering, software engineering, among others. Root mean squareIn mathematics and its applications, the root mean square (RMS or rms) is defined as the square root of the mean square (the arithmetic


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-15.md
category: reference
title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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parent: glossary-of-engineering-m-z-20260505-0
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Safe failure fraction (SFF)A term used in functional safety for the proportion of failures that are either non-hazardous or detected automatically. The opposite of SFF is the proportion of undetected, hazardous failures. Safety data sheetA safety data sheet (SDS), material safety data sheet (MSDS), or product safety data sheet (PSDS) are documents that list information relating to occupational safety and health for the use of various substances and products. SDSs are a widely used system for cataloguing information on chemicals, chemical compounds, and chemical mixtures. SDS information may include instructions for the safe use and potential hazards associated with a particular material or product, along with spill-handling procedures. The older MSDS formats could vary from source to source within a country depending on national requirements; however, the newer SDS format is internationally standardized. Sanitary engineeringSanitary engineering, also known as public health engineering or wastewater engineering, is the application of engineering methods to improve sanitation of human communities, primarily by providing the removal and disposal of human waste, and in addition to the supply of safe potable water. Saturated compoundIn chemistry, a saturated compound is a chemical compound (or ion) that resists the addition reactions, such as hydrogenation, oxidative addition, and


id: glossary-of-engineering-m-z-20260505-16
file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-16.md
category: reference
title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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Shortwave radiation is distinguished from longwave radiation. Downward shortwave radiation is sensitive to solar zenith angle, cloud cover. SI unitsThe International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system. It is the only system of measurement with an official status in nearly every country in the world. It comprises a coherent system of units of measurement starting with seven base units, which are the second (the unit of time with the symbol s), metre (length, m), kilogram (mass, kg), ampere (electric current, A), kelvin (thermodynamic temperature, K), mole (amount of substance, mol), and candela (luminous intensity, cd). The system allows for an unlimited number of additional units, called derived units, which can always be represented as products of powers of the base units. Twenty-two derived units have been provided with special names and symbols. The seven base units and the 22 derived units with special names and symbols may be used in combination to express other derived units, which are adopted to facilitate measurement of diverse quantities. The SI also provides twenty prefixes to the unit names and unit symbols that may be used when specifying power-of-ten (i.e. decimal)


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-17.md
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title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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Specifically, the Stefan–Boltzmann law states that the total energy radiated per unit surface area of a black body across all wavelengths per unit time j ⋆ {\displaystyle j^{\star }} (also known as the black-body radiant emittance) is directly proportional to the fourth power of the black body's thermodynamic temperature T:


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-18.md
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title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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j ⋆ = σ T 4 . {\displaystyle j^{\star }=\sigma T^{4}.} The constant of proportionality σ, called the Stefan–Boltzmann constant, is derived from other known physical constants. Since 2019, the value of the constant is σ = 2 π 5 k 4 15 c 2 h 3 = 5.670374 … × 10 − 8 W m − 2 K − 4 , {\displaystyle \sigma ={\frac {2\pi ^{5}k^{4}}{15c^{2}h^{3}}}=5.670374\ldots \times 10^{-8}\,\mathrm {W\,m^{-2}\,K^{-4}} ,} where k is the Boltzmann constant, h is the Planck constant, and c is the speed of light in vacuum. The radiance from a specified angle of view (watts per square metre per steradian) is given by L = j ⋆ π = σ π T 4 . {\displaystyle L={\frac {j^{\star }}{\pi }}={\frac {\sigma }{\pi }}T^{4}.} A body that does not absorb all incident radiation (sometimes known as a grey body) emits less total energy than a black body and is characterized by an emissivity, ε < 1 {\displaystyle \varepsilon <1} : j ⋆ = ε σ T 4 . {\displaystyle j^{\star }=\varepsilon \sigma T^{4}.} The radiant emittance j ⋆ {\displaystyle j^{\star }} has dimensions of energy flux (energy per unit time per unit area), and the SI units


id: glossary-of-engineering-m-z-20260505-19
file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-19.md
category: reference
title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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In simple terms we can define stress as the force of resistance per unit per unit area, offered by a body against deformation. Stress is the ratio of force over area (S =R/A, where S is the stress, R is the internal resisting force and A is the cross-sectional area). Strain is the ratio of change in length to the original length, when a given body is subjected to some external force (Strain= change in length÷the original length). Stress–strain curveIn engineering and materials science, a stress–strain curve for a material gives the relationship between stress and strain. It is obtained by gradually applying load to a test coupon and measuring the deformation, from which the stress and strain can be determined (see tensile testing). These curves reveal many of the properties of a material, such as the Young's modulus, the yield strength and the ultimate tensile strength. Structural analysisis the determination of the effects of loads on physical structures and their components. Structures subject to this type of analysis include all that must withstand loads, such as buildings, bridges, aircraft and ships. Structural analysis employs the fields of applied mechanics, materials science and applied mathematics to compute a structure's deformations,


id: glossary-of-engineering-m-z-20260505-20
file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-20.md
category: reference
title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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a = d v d t = d v d t u t + v ( t ) d u t d t = d v d t u t + v 2 r u n , {\displaystyle {\begin{alignedat}{3}\mathbf {a} &={\frac {d\mathbf {v} }{dt}}\\&={\frac {dv}{dt}}\mathbf {u} _{\mathrm {t} }+v(t){\frac {d\mathbf {u} _{\mathrm {t} }}{dt}}\\&={\frac {dv}{dt}}\mathbf {u} _{\mathrm {t} }+{\frac {v^{2}}{r}}\mathbf {u} _{\mathrm {n} }\ ,\end{alignedat}}} where un is the unit (inward) normal vector to the particle's trajectory (also called the principal normal), and r is its instantaneous radius of curvature based upon the osculating circle at time t. These components are called the tangential acceleration and the normal or radial acceleration (or centripetal acceleration in circular motion, see also circular motion and centripetal force). Geometrical analysis of three-dimensional space curves, which explains tangent, (principal) normal and binormal, is described by the Frenet–Serret formulas. Technical standardA technical standard is an established norm or requirement for a repeatable technical task. It is usually a formal document that establishes uniform engineering or technical criteria, methods, processes, and practices. In contrast, a custom, convention, company product, corporate standard, and so forth that becomes generally accepted and dominant is often called a de facto standard.


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-21.md
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title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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Systems in thermodynamic equilibrium are always in thermal equilibrium, but the converse is not always true. If the connection between the systems allows transfer of energy as 'change in internal energy' but does not allow transfer of matter or transfer of energy as work, the two systems may reach thermal equilibrium without reaching thermodynamic equilibrium. Thermal radiationis electromagnetic radiation generated by the thermal motion of particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation. Particle motion results in charge-acceleration or dipole oscillation which produces electromagnetic radiation. Thermodynamicsis a branch of physics that deals with heat, work, and temperature, and their relation to energy, radiation, and physical properties of matter. The behavior of these quantities is governed by the four laws of thermodynamics which convey a quantitative description using measurable macroscopic physical quantities, but may be explained in terms of microscopic constituents by statistical mechanics. Thermodynamics applies to a wide variety of topics in science and engineering, especially physical chemistry, biochemistry, chemical engineering and mechanical engineering, but also in other complex fields such as meteorology. Theory of relativityusually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-22.md
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title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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Transducers are often employed at the boundaries of automation, measurement, and control systems, where electrical signals are converted to and from other physical quantities (energy, force, torque, light, motion, position, etc.). The process of converting one form of energy to another is known as transduction. Transformeris a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any one coil of the transformer produces a varying magnetic flux in the transformer's core, which induces a varying electromotive force across any other coils wound around the same core. Electrical energy can be transferred between separate coils without a metallic (conductive) connection between the two circuits. Faraday's law of induction, discovered in 1831, describes the induced voltage effect in any coil due to a changing magnetic flux encircled by the coil. Trigonometric functionsIn mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are real functions which relate an angle of a right-angled triangle to ratios of two side lengths. They are widely used in all sciences that are related to geometry, such as navigation, solid mechanics, celestial mechanics, geodesy, and many others. They are among the simplest periodic


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-23.md
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title: Glossary of engineering: M–Z
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source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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Ultimate tensile strengthUltimate tensile strength (UTS), often shortened to tensile strength (TS), ultimate strength, or Ftu within equations, is the capacity of a material or structure to withstand loads tending to elongate, as opposed to compressive strength, which withstands loads tending to reduce size. In other words, tensile strength resists tension (being pulled apart), whereas compressive strength resists compression (being pushed together). Ultimate tensile strength is measured by the maximum stress that a material can withstand while being stretched or pulled before breaking. In the study of strength of materials, tensile strength, compressive strength, and shear strength can be analyzed independently. Uncertainty principleIn quantum mechanics, the uncertainty principle (also known as Heisenberg's uncertainty principle) is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position x and momentum p, can be known. UnicodeA standard for the consistent encoding of textual characters. Unit vectorIn mathematics, a unit vector in a normed vector space is a vector (often a spatial vector) of length 1. A unit vector is often denoted by a lowercase letter with a circumflex, or "hat": ı ^


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-24.md
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title: Glossary of engineering: M–Z
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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Vacuoleis a membrane-bound organelle which is present in plant and fungal cells and some protist, animal and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain cases they may contain solids which have been engulfed. Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these. The organelle has no basic shape or size; its structure varies according to the requirements of the cell. VacuumAn absence of mass in a volume. ValenceIn chemistry, the valence or valency of an element is a measure of its combining power with other atoms when it forms chemical compounds or molecules. The concept of valence developed in the second half of the 19th century and helped successfully explain the molecular structure of inorganic and organic compounds. The quest for the underlying causes of valence led to the modern theories of chemical bonding, including the cubical atom (1902), Lewis structures (1916), valence bond theory (1927), molecular orbitals (1928), valence shell electron pair repulsion theory (1958), and all of the advanced methods of quantum chemistry. Valence bandIn solid-state physics, the valence band and conduction


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-25.md
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title: Glossary of engineering: M–Z
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where Vm is the molar volume of the gas, R is the universal gas constant, T is temperature, P is pressure, and V is volume. When the molar volume Vm is large, b becomes negligible in comparison with Vm, a/Vm2 becomes negligible with respect to P, and the Van der Waals equation reduces to the ideal gas law, PVm=RT. It is available via its traditional derivation (a mechanical equation of state), or via a derivation based in statistical thermodynamics, the latter of which provides the partition function of the system and allows thermodynamic functions to be specified. It successfully approximates the behavior of real fluids above their critical temperatures and is qualitatively reasonable for their liquid and low-pressure gaseous states at low temperatures. However, near the phase transitions between gas and liquid, in the range of p, V, and T where the liquid phase and the gas phase are in equilibrium, the Van der Waals equation fails to accurately model observed experimental behaviour, in particular that p is a constant function of V at given temperatures. As such, the Van der Waals model is not useful only for calculations intended to predict real behavior in regions near the critical point.


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-26.md
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title: Glossary of engineering: M–Z
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source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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Viscoelastic materials have elements of both of these properties and, as such, exhibit time-dependent strain. Whereas elasticity is usually the result of bond stretching along crystallographic planes in an ordered solid, viscosity is the result of the diffusion of atoms or molecules inside an amorphous material. ViscosityThe viscosity of a fluid is the measure of its resistance to gradual deformation by shear stress or tensile stress. For liquids, it corresponds to the informal concept of "thickness": for example, honey has a higher viscosity than water. Volt-ampere(VA), is the unit used for the apparent power in an electrical circuit. The apparent power equals the product of root-mean-square (RMS) voltage and RMS current. In direct current (DC) circuits, this product is equal to the real power (active power) in watts. Volt-amperes are useful only in the context of alternating current (AC) circuits. The volt-ampere is dimensionally equivalent to the watt (in SI units, 1 VA = 1 N m A−1 s −1 A = 1 N m s −1 = 1 J s −1 = 1 W). VA rating is most useful in rating wires and switches (and other power handling equipment) for inductive loads. Volt-ampere reactiveIn electric power transmission and distribution,


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-27.md
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title: Glossary of engineering: M–Z
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source_url: https://en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z
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WattThe SI unit of power, rate of doing work. Waveis a disturbance that transfers energy through matter or space, with little or no associated mass transport. Waves consist of oscillations or vibrations of a physical medium or a field, around relatively fixed locations. From the perspective of mathematics, waves, as functions of time and space, are a class of signals. Wavelengthis the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is thus the inverse of the spatial frequency. Wavelength is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. Wavelength is commonly designated by the Greek letter lambda (λ). The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.' . Wedgeis a triangular shaped tool, and is a portable inclined plane, and one of the six classical simple machines. It can be used to separate two objects or portions of an object, lift up an object, or hold


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file: data/en.wikipedia.org/wiki/Glossary_of_engineering:_M–Z-28.md
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title: Glossary of engineering: M–Z
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Reasons for zero-force members in a truss system These members contribute to the stability of the structure, by providing buckling prevention for long slender members under compressive forces These members can carry loads in the event that variations are introduced in the normal external loading configuration. Zeroth law of thermodynamicsThe equivalence principle applied to temperature; two systems in thermal equilibrium with a third are also in thermal equilibrium with each other. == See also == == Notes == == References == == Sources == Boyer, Carl B. (1991). A History of Mathematics (Second ed.). John Wiley & Sons, Inc. ISBN 978-0-471-54397-8. Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Manufacturing (9th ed.), Wiley, ISBN 978-0-471-65653-1. Dodge, Y. (2003). The Oxford dictionary of Statistical Terms. Oxford University Press. ISBN 0-19-920613-9. Holzner, S. (2006). Physics for Dummies. John Wiley & Sons. Bibcode:2005pfd..book.....H. ISBN 978-0-470-61841-7. Physics is the study of your world and the world and universe around you. Maxwell, J.C. (1994) [1st Pub. 1878]. Matter and Motion. D. Van Nostrand. ISBN 978-0-486-66895-6. matter and motion. Smith, William F.; Hashemi, Javad (2006), Foundations of Materials Science and Engineering (4th ed.), McGraw-Hill, ISBN 978-0-07-295358-9. Young, H.D.; Freedman, R.A.


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file: data/en.wikipedia.org/wiki/Glossary_of_environmental_science-0.md
category: reference
title: Glossary of environmental science
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_environmental_science
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This is a glossary of environmental science. Environmental science is the study of interactions among physical, chemical, and biological components of the environment. Environmental science provides an integrated, quantitative, and interdisciplinary approach to the study of environmental systems. == 0-9 == 1-in-100 flood – a flood with 1 in 100 chance of occurring in any given year (used as a safety requirement for the construction industry.) 20/30/10 standard - 20 mg/L Biochemical Oxygen Demand (BOD), 30 mg/L Suspended Solids (SS), 10 units of E. coli: the water quality standard for greywater use in toilets, laundry and surface irrigation. 5Rs - (sustainability) reduce, remanufacture, reuse, recycle, recover. == A == abiotic component - Any non-living chemical or physical part of the environment that affects living organisms and the functioning of ecosystems, such as the atmosphere and water resources. (see also biotic). absorption pit (soakaway) – a hole dug in permeable ground and filled with broken stones or granular material and usually covered with earth allowing collected water to soak into the ground. absorption - one substance taking in another, either physically or chemically. acclimation - the process of an organism adjusting to chronic change in its environment. acid mine drainage -


id: glossary-of-environmental-science-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_environmental_science-1.md
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title: Glossary of environmental science
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_environmental_science
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== B == backflow - movement of water back to source e.g. contaminated water in a plumbing system. baffle - (landscape design) an obstruction to trap debris in drainage water. bagasse - the fibrous residue of sugar cane milling used as a fuel to produce steam in sugar mills. baseload - the steady and reliable supply of energy through the grid. This is punctuated by bursts of higher demand known as “peak-load”. Supply companies must be able to respond instantly to extreme variation in demand and supply, especially during extreme conditions. Gas generators can react quickly while coal is slow but provides the steady "baseload". Renewable energies are generally not available on demand in this way. batters - (landscape design) the slope of earthworks such as drainage channels. best practice - a process, or innovative use of technology, equipment or resources or other measurable factors that have a proven record of success. bioaccumulation - the accumulation of a substance, such as a toxic chemical, in the tissues of a living organism. biocapacity - a measure of the biological productivity of an area. This may depend on natural conditions or human inputs like farming and forestry practices; the area needed to


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== C == C3 & C4 plants – C4 plants comprise about 5% of all plants, are most abundant in hot and arid conditions, and include crops like sugar cane and soybeans. During photosynthesis they form molecules with 4-carbon atoms and saturate at the given level of CO2. C3 plants, the other 95%, photosynthesise to form 3 carbon molecules and increase photosynthesis with as CO2 levels increase. calorie – a basic measure of energy that has been replaced by the SI unit the joule; in physics it approximates the energy needed to increase the temperature of 1 gram of water by 1 °C which is about 4.184 joules. The Calories in food ratings (spelled with a capital C) and nutrition are ‘big C’ Calories or kcal. calorific value – the energy content of a fuel measured as the heat released on complete combustion. cancer – a group of diseases in which cells are aggressive (grow and divide without respect to normal limits), invasive (invade and destroy adjacent tissues), and sometimes metastatic (spread to other locations in the body). capillary action (wicking) – water drawn through a medium by surface tension. car pooling – giving people lifts to help reduce emissions


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title: Glossary of environmental science
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soil), asphalt, bricks and timber. C&D waste excludes construction waste which is included in the municipal waste stream. C&D waste does not generally include waste from the commercial and industrial waste stream. consumer democracy – using your economic capacity to promote your values. consumer – organism, human being, or industry that maintains itself by transforming a high-quality energy source into a lower one cf. Producer, primary production. consumption (ecology) – the use of resources by a living system, the inflow and degradation of energy that is used for system activity. consumption (economics) – part of disposable income (income after taxes paid and payments received) that is not saved, essentially the goods and services used by households; this includes purchased commodities at the household level (such as food, clothing, and utilities), the goods and services paid for by government (such as defence, education, social services and health care), and the resources consumed by businesses to increase their assets (such as business equipment and housing). contour ploughing (contour farming) – the farming practice of plowing across a slope following its contours. The rows formed have the effect of slowing water run-off during rainstorms so that the soil is not washed away and


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file: data/en.wikipedia.org/wiki/Glossary_of_environmental_science-4.md
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title: Glossary of environmental science
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== D == DDT - a chlorinated hydrocarbon used as a pesticide that is a persistent organic pollutant. debt-for-Nature Swap - a financial transaction in which a portion of a developing nation's foreign debt is forgiven in exchange for local investments in conservation measures. decomposers – consumers, mostly microbial, that change dead organic matter into minerals and heat. deforestation - the conversion of forested areas to non-forest land for agriculture, urban use, development, or wasteland. dematerialisation – decreasing the consumption of materials and resources while maintaining quality of life. desalination producing potable or recyclable water by removing salts from salty or brackish water. This is done by three methods: distillation/freezing; reverse osmosis using membranes and electrodialysis; ion exchange. At present, all these methods are energy intensive. desert – an area that receives an average annual precipitation of less than 250 mm (9.8 in) or an area in which more water is lost than falls as precipitation. desertification - the degradation of land in arid, semi arid and dry sub-humid areas resulting from various climatic variations, but primarily from human activities. detritivore (detritus feeder) - animals and plants that consume detritus (decomposing organic material), and in doing so contribute to decomposition


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file: data/en.wikipedia.org/wiki/Glossary_of_environmental_science-5.md
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title: Glossary of environmental science
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== E == eco- - a prefix now added to many words indicating a general consideration for the environment e.g. ecohousing, ecolabel, ecomaterial. eco-asset – a biological asset that provides financial value to private land owners when they are maintained in or restored to their natural state. ecolabel - seal or logo indicating a product has met a certain environmental or social standards. ecological deficit - of a country or region measures the amount by which its Ecological Footprint exceeds the ecological capacity of that region. Ecological Footprint (Eco-footprint, Footprint)– a measure of the area of biologically productive land and water needed to produce the resources and absorb the wastes of a population using the prevailing technology and resource management schemes; a measure of the consumption of renewable natural resources by a human population, be it that of a country, a region or the whole world given as the total area of productive land or sea required to produce all the crops, meat, seafood, wood and fibre it consumes, to sustain its energy consumption and to give space for its infrastructure. ecological niche - the habitat of a species or population within its ecosystem. ecological succession - the more-or-less predictable


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title: Glossary of environmental science
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coiled springs and charged batteries have potential energy; * primary energy – forms of energy obtained directly from nature, the energy in raw fuels (electricity from the grid is not primary energy), used mostly in energy statistics when compiling energy balances; * solar energy – solar radiation used for hot water production and electricity generation (does not include passive solar energy to heat and cool buildings etc.); * secondary energy – primary energies are transformed in energy conversion processes to more convenient secondary forms such as electrical energy and cleaner fuels; * stationary energy – that energy that is other than transport fuels and fugitive emissions, used mostly for production of electricity but also for manufacturing and processing and in agriculture, fisheries etc.; * tidal/ocean/wave energy– mechanical energy from water movement used to generate electricity; * useful energy – available energy used to increase system production and efficiency; * wind energy – kinetic energy of wind used for electricity generation using turbines energy accounting – measuring value by the energy input required for a good or service. A form of accounting that builds in a measure of our impact on nature (rather than being restricted to human-based items). energy audit


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title: Glossary of environmental science
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== F == feedback – flow from the products of an action back to interact with the action. feedlot (feedyard) - a type of Confined Animal Feeding Operation (CAFO) (also known as "factory farming") which is used for finishing livestock, notably beef cattle, prior to slaughter. fertigate – apply fertiliser through an irrigation system. fertility rate - number of live births per 1,000 women aged 15 to 44 years cf. birth rate, mortality rate. fertilizers (also spelled fertilisers) - compounds given to plants to promote growth; they are usually applied either through the soil, for uptake by plant roots, or by foliar feeding, for uptake through leaves. flyway - the flight paths used in bird migration. Flyways generally span over continents and often oceans. food chain (food webs, food networks and/or trophic networks) - the feeding relationships between species within an ecosystem. food miles - the emissions produced and resources needed to transport food and drink around the globe. food security - food produced in sufficient quantity to meet the full requirements of all people i.e. total global food supply equals the total global demand. For households it is the ability to purchase or produce the food they need for


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== G == G8 - The Group of Eight is an international forum for the world's major industrialised democracies that emerged following the 1973 oil crisis and subsequent global recession. It includes Canada, France, Germany, Italy, Japan, Russia, the UK and the US which represents about 65% of the world economy. Gaia hypothesis - an ecological hypothesis that proposes that living and nonliving parts of the earth are a complex interacting system that can be thought of as a single organism. gene pool - the complete set of unique alleles in a species or population. generalist species - those able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources. gene - a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with regulatory regions, transcribed regions and/or other functional sequence regions. genetic diversity - one of the three levels of biodiversity that refers to the total number of genetic characteristics. greenhouse effect - the process in which the emission of infrared radiation by the atmosphere warms a planet's surface. greenhouse gas - components of the atmosphere that contribute to the greenhouse effect. green manure -


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greywater – household waste water that has not come into contact with toilet waste; includes water from baths, showers, bathrooms, washing machines, laundry and kitchen sinks. gross primary productivity - total carbon assimilation. groundwater – water found below the surface – usually in porous rocks, or soil, or in underground aquifers. growth – increase in size, weight, power etc.


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== H == habitat - an ecological or environmental area that is inhabited by a particular species. hard waste - household garbage which is not normally accepted into rubbish bins by local councils, e.g. old stoves, mattresses. heat– energy derived from the motion of molecules; a form of energy into which all other forms of energy may be degraded. herbicide – a chemical the kills or inhibits growth of a plant. herbivory - predation in which an organism known as an herbivore, consumes principally autotrophs such as plants, algae and photosynthesizing bacteria. heterotroph (chemoorganotrophy) - an organism that requires organic substrates to obtain its carbon for growth and development. hierarchy – an organisation of parts in which control from the top (generally with few parts), proceeds through a series of levels (ranks) to the bottom (generally of many parts) cf. heterarchy. high-density polyethylene (HDPE) - A member of the polyethylene family of plastics and is used to make products such as milk bottles, pipes and shopping bags. HDPE may be coloured or opaque. homoclime – a region with the same climate as the one under investigation. horsepower (hp) = 745.7 watts. homeostasis - the property of either an open system


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== I == incineration - combustion (by chemical oxidation) of waste material to treat or dispose of that waste material. indicator species - any biological species that defines a trait or characteristic of the environment. industrial agriculture - a form of modern farming that involves industrialized production of livestock, poultry, fish, and crops. Industrial Revolution - a period in the late 18th and early 19th centuries when major changes in agriculture, manufacturing, and transportation had a profound effect on socioeconomic and cultural conditions. infiltration – movement of water below topsoil to the plant roots and below. infiltration - the process by which water on the ground surface enters the soil. indicators– quantitative markers for monitoring progress towards desired goals. industrial ecology (term int. Harry Zvi Evan 1973) - the observation that nature produces no waste and therefore provides an example of sustainable waste management. Natural Capitalism espouses industrial ecology as one of its four pillars together with energy conservation, material conservation, and redefinition of commodity markets and product stewardship in terms of a service economy. Publications: insecticide - a pesticide used to control insects in all developmental forms. Integrated Pest Management (IPM) - a pest control strategy that uses an


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title: Glossary of environmental science
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leachate (waste) - the mixture of water and dissolved solids (possibly toxic) that accumulates as water passes through waste and collects at the bottom of a landfill site. leaf area index (LAI) – the ratio of photosynthetic leaf area to ground area covered (optimal for photosynthesis = 3-5). LAI is often optimised by shifts in leaf angle, a form of solar tracking. 'level (scale, context or framework) – a context, frame of reference or degree of organisation within an integrated system. A level may or may not be spatially delimited. life cycle (of a product) - All stages of a product's development, from raw materials, manufacturing through to consumption and ultimate disposal. Life Cycle Analysis (LCA) - an objective process to evaluate the environmental impacts associated with a product, process, or activity. A means of identifying resource use and waste released to the environment, and to assess management options. life support systems - according to the World Conservation Union (IUCN), the biophysical processes "that sustain the productivity, adaptability and capacity for renewal of lands, waters, and / or the biosphere as a whole." lilacwater – recycled water that is unsuitable for drinking. linear low-density polyethylene - a member of the


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== N == National Packaging Covenant - a self-regulatory agreement between packaging industries and government. natural- the existing air, water, land and energy resources from which all resources derive. Main functions include resource production (such as fish, timber or cereals), waste assimilation (such as CO2 absorption, sewage decomposition), and life support services (UV protection, biodiversity, water cleansing, climate stability). The environmental services that must be maintained so that human development can be sustainable. natural capital - natural resources and ecological processes that are equivalent to financial capital. natural resources - naturally occurring substances that are considered valuable in their relatively unmodified (natural) form. natural selection - the process by which favorable heritable traits become more common in successive generations of a population of reproducing organisms, and unfavorable heritable traits become less common. nature-positive - a global societal goal to halt and reverse nature loss by 2030, measured from a 2020 baseline, and with the aim of achieving full recovery by 2050. neighbourhood environment improvement plan - plans developed by a local community including residents, special interest groups, local government, local industry and government agencies. nematocide – a chemical that kills nematodes. net primary production - the energy or biomass content


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== P == Patterns in nature - are visible regularities of form found in the natural world. pay-by-weight systems - financial approaches to managing waste that charge prices according to the quantity of waste collected, rather than a price per pick-up or fixed annual charge, as typically applied to households for kerbside services. Pay-by-weight systems may provide an incentive to reduce waste generation. per capita consumption - the average amount of commodity used per person. Persistent organic pollutants (POPs) - organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. pervious surface – one which can be penetrated by air and water. pesticide - means any substance or mixture of substances intended for preventing, destroying or controlling any pest. This includes substances intended for use as a plant growth regulator, defoliant, desiccant, or agent for thinning fruit or preventing the premature fall of fruit, and substances applied to crops either before or after harvest to protect the commodity from deterioration during storage and transport. (Food and Agriculture Organization of the United Nations, 2003). photosynthesis – the transformation of radiant energy to chemical energy by plants; the manufacture by plants of carbohydrates from carbon dioxide and water.


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== R == radiative forcing - changes in the energy balance of the earth-atmosphere system in response to a change in factors such as greenhouse gases, land-use change, or solar radiation. Positive radiative forcing increases the temperature of the lower atmosphere, which in turn increases temperatures at the Earth's surface. Negative radiative forcing cools the lower atmosphere. Radiative forcing is most commonly measured in units of watts per square meter (W/m2). rain garden – an engineered area for the collection, infiltration and evapotranspiration of rainwater runoff, mostly from impervious surfaces; it reduces rain runoff by allowing stormwater to soak into the ground (as opposed to flowing into storm drains and surface waters which can cause erosion, water pollution, flooding, and diminished groundwater). They can also absorb water contaminants that would otherwise end up in water bodies. The terminology arose in Maryland, USA in the 1990s as a more marketable expression for bioremediation. rainwater harvesting – collecting rainwater either in storages or the soil mostly close to where it falls; the attempt to increase rainwater productivity by storing it in pondages, wetlands etc., and helping to avoid the need for infrastructure to bring water from elsewhere. Practiced on a large scale


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== S == salinisation – (ecology) the process by which land becomes salt-affected. salinity – (ecology) salt in water and soils, generally in the context of human activity such as clearing and planting for annual crops rather than perennial trees and shrubs. Can make soils infertile. scale – the physical dimensions, in either space or time, of phenomena or events; cf. a level which may or may not have a scale. sectors – (economics) economic groupings used to generalise patterns of expenditure and use. sediment – (ecology) soil or other particles that settle to the bottom of water bodies. self-organisation – the process by which systems use energy to develop structure and organisation. sentinel indicator – (ecology) an indicator that captures the essence of the process of change affecting a broad area of interest and which is also easily communicated. septic sewage – sewage in which anaerobic respiration is taking place characterised by a blackish colour and smell of hydrogen sulphide. septic tank - a type of sedimentation tank in which the sludge is retained long enough for the organic content to undergo anaerobic digestion. Typically used for receiving the sewage from houses and other premises that are too isolated


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State Environment Protection Policies - statutory instruments under the Environment Protection Act 1970 that identify beneficial uses of the environment that are to be protected, establish environmental indicators and objectives and define attainment programs to implement the policies. State of the Environment reporting - a scientific assessment of environmental conditions, focusing on the impacts of human activities, their significance for the environment and social responses to the identified trends. steady state – a constant pattern e.g. a balance of inflows and outflows. stormwater – rainfall that accumulates in natural or artificial systems after heavy rain; surface run-off or water sent to (stormwater) drains during heavy rain. strategic Environmental Assessment (SEA) - a system of incorporating environmental considerations into policies, plans and programs esp in the EU. sullage – domestic waste water from baths, basins, showers, laundries, kitchens and floor waste (but not from toilets). Superfund –a United States federal government program designed to fund the cleanup of sites contaminated with hazardous substances and pollutants. It was established as the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). supporting services – (sustainability) ecosystem services that are necessary for the production of all other ecosystem services e.g. biomass production, production


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== T == take-back - a concept commonly associated with product stewardship, placing responsibility on brand-owners, retailers, manufacturers or other supply chain partners to accept products returned by consumers once they have reached the end of their useful life. Products may then be recycled, treated or sent to landfill. technosphere – synthetic and composite components and materials for med by human activity. True technosphere materials, like plastics, are not biodegradable. temperate – with moderate temperatures, weather, or climate; neither hot nor cold; mean annual temperature between 0 – 20 deg C. thermal mass – (architecture) any mass that can absorb and store heat and can therefore be used to buffer temperature change. Concrete, bricks and tiles need a lot of heat energy to change their temperature and therefore have high thermal mass, timber has low thermal mass. third pipe system – a third pipe, in addition to the standard water supply pipe and sewer disposal pipe, which carries recycled water for irrigation purposes. threshold – (ecology) a point that, when crossed, can bring rapid and sometimes unpredictable change in a trend. An example would be the sudden altering of ocean currents due to the melting of ice at the poles.


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== W == waste - any material (liquid, solid or gaseous) that is produced by domestic households and commercial, institutional, municipal or industrial organisations, and which cannot be collected and recycled in any way for further use. For solid wastes, this involves materials that currently go to landfills, even though some of the material is potentially recyclable. waste analysis -the quantifying of different waste streams, recording and detailing of it as a proportion of the total waste stream, determining its destination and recording details of waste practices. waste assessment - observing, measuring, and recording data and collecting and analysing waste samples. Some practitioners consider an assessment to be one where observations are carried out visually, without sorting and measuring individual streams (see visual waste audit). waste audit -see waste assessment. waste avoidance – primary pillar of the waste hierarchy; avoidance works on the principle that the greatest gains result from efficiency-centred actions that remove or reduce the need to consume materials in the first place, but deliver the same outcome. waste factors - (used in round-wood calculations) give the ratio of one cubic metre of round wood used per cubic metre (or tonne) of product. waste generation - generation of


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== Z == zero waste – turning waste into resource; the redesign of resource-use so that waste can ultimately be reduced to zero; ensuring that by-products are used elsewhere and goods are recycled, in emulation of the cycling of wastes in nature. == See also == Environmental science Climate change acronyms Glossary of climate change List of environmental issues List of sustainability topics == References == == External links == Environmental Terminology Discovery Service — EEA (multilingual environmental glossary in 28 languages: ar, bg, cs, da, de, el, en, es, et, eu, fi, fr, hu, is, it, lt, lv, mt, nl, no, pl, pt, ro, ru, sk, sl, sv, tr)


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title: Glossary of experimental design
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A glossary of terms used in experimental research. == Concerned fields == Statistics Experimental design Estimation theory


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== Glossary == Alias: When the estimate of an effect also includes the influence of one or more other effects (usually high order interactions) the effects are said to be aliased (see confounding). For example, if the estimate of effect D in a four factor experiment actually estimates (D + ABC), then the main effect D is aliased with the 3-way interaction ABC. Note: This causes no difficulty when the higher order interaction is either non-existent or insignificant. Analysis of variance (ANOVA): A mathematical process for separating the variability of a group of observations into assignable causes and setting up various significance tests. Balanced design: An experimental design where all cells (i.e. treatment combinations) have the same number of observations. Blocking: A schedule for conducting treatment combinations in an experimental study such that any effects on the experimental results due to a known change in raw materials, operators, machines, etc., become concentrated in the levels of the blocking variable. Note: the reason for blocking is to isolate a systematic effect and prevent it from obscuring the main effects. Blocking is achieved by restricting randomization. Center Points: Points at the center value of all factor ranges. Coding Factor Levels: Transforming the


id: glossary-of-experimental-design-20260505-2
file: data/en.wikipedia.org/wiki/Glossary_of_experimental_design-2.md
category: reference
title: Glossary of experimental design
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_experimental_design
date_saved: 2026-05-05T07:50:51.786573+00:00
instance: kb-cron
parent: glossary-of-experimental-design-20260505-0
summary:
Lack of fit error: Error that occurs when the analysis omits one or more important terms or factors from the process model. Note: Including replication in a designed experiment allows separation of experimental error into its components: lack of fit and random (pure) error. Model: Mathematical relationship which relates changes in a given response to changes in one or more factors. Nested Factors: See factors above. Orthogonality: Two vectors of the same length are orthogonal if the sum of the products of their corresponding elements is 0. Note: An experimental design is orthogonal if the effects of any factor balance out (sum to zero) across the effects of the other factors. Paradigm: a model created given the basic design, the hypothesis and the particular conditions for the experiment. Random effect: An effect associated with input variables chosen at random from a population having a large or infinite number of possible values. Random error: Error that occurs due to natural variation in the process. Note: Random error is typically assumed to be normally distributed with zero mean and a constant variance. Note: Random error is also called experimental error. Randomization: A schedule for allocating treatment material and for conducting treatment combinations


id: glossary-of-geology-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_geology-0.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
This glossary of geology is a list of definitions of terms and concepts relevant to geology, its sub-disciplines, and related fields. For other terms related to the Earth sciences, see Glossary of geography terms (disambiguation). == A == abiotic Non-living chemical or physical component of the environment affecting living organisms and the functioning of ecosystems. abyssal plain A flat or very gently sloping area on the floor of a deep ocean basin. absolute dating The process of determining a specific date (in years or some other unit of time) for an archaeological, geological or paleontological site or artifact. accident A sudden discontinuity of ground, such as a fault of great thickness, bed or lentil of unstable ground. accretion A process by which material is added to a tectonic plate or landmass. achnelith A small, glassy volcanic bomb, sphere, dumbbell, or droplet-shaped stone resulting from very liquid magma. acid rock The groups ultrabasic, basic, intermediate and acid constitute a series with progressively increasing SiO2 content. aftershock A small earthquake that follows a main shock. agglomerate An indurated rock built of large angular rock fragments embedded in an ashy matrix and resulting from explosive volcanic activity. Occurs typically in volcanic vents. aggregate


id: glossary-of-geology-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_geology-1.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
autochthon A fossil, sediment, or rock that was formed or produced in the location where it is now found. The term is widely applied to a coal or peat that originated at the place where the plants comprising it grew and decayed and to rocks that have not been displaced by overthrust faulting. An object of this type is referred to as autochthonous. Contrast allochthon. == B == bajada A series of coalescing alluvial fans along a mountain front. banded iron formation A distinctive type of rock often found in primordial sedimentary rocks. basalt A fine-grained, mafic igneous rock composed predominantly of ferromagnesian minerals and with lesser amounts of calcium-rich plagioclase feldspar. basement rock The thick foundation of ancient, and oldest metamorphic and igneous rock that forms the crust of continents, often in the form of granite. basic rock Igneous rock with low silica content (<54%). The groups ultrabasic, basic, intermediate, and acid constitute a series with progressively increasing SiO2 content. basin A landform scooped out by water erosion. Basin and Range Province A particular topography covering much of the southwestern United States and northwestern Mexico that is typified by elongate north-south trending arid valleys bounded by mountain ranges which


id: glossary-of-geology-20260505-2
file: data/en.wikipedia.org/wiki/Glossary_of_geology-2.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
cleavage The tendency of a rock to break along preferred planes of weakness, caused by the development of a planar fabric as a result of deformation. cobble coccolith An individual plate of calcium carbonate formed by coccolithophores which are arranged around them in a so-called coccosphere. coccolithophore Also called a coccolithophorid. A type of microfossil of single-celled algae, protists and phytoplankton belonging to the division of haptophytes. These fossils are distinguished by special calcium carbonate plates called coccoliths. compaction The process by which a newly deposited sediment decreases its porosity and progressively expels its original pore water due to the effects of loading. This forms part of the process of lithification. compression The process by which rocks shorten or decrease in volume when exposed to certain forces. conchoidal A type of fracture that results in smoothly curved surface faces. concretion A volume of sedimentary rock in which a mineral cement fills the porosity (i.e. the spaces between the sediment grains). Not to be confused with nodule. conglomerate Any type of rock consisting of individual stones that have become cemented together. contact metamorphism Metamorphism due to the local heating of rocks by the intrusion of magma nearby. continental crust The layer


id: glossary-of-geology-20260505-3
file: data/en.wikipedia.org/wiki/Glossary_of_geology-3.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
dolerite 1. A basic igneous rock of medium grain size, occurring as minor intrusions or in the central parts of thick lava flows. 2. A dark-coloured, basic, igneous rock, composed essentially of pyroxene and a triclinic feldspar with magnetic iron. Considered by some authors to be equivalent to a coarse-grained basalt. 3. A dark, crystalline, igneous rock, chiefly pyroxene with labradorite. 4. Coarse-grained basalt. 5. Diabase. 6. Any dark igneous rock composed chiefly of silicates of iron and magnesium with some feldspar. dome A geological formation consisting of symmetrical anticlines that intersect each other at their respective apices. drill core A drill specifically designed to remove a cylinder of material, much like a hole saw. drumlin An elongated, whale-shaped hill formed by glacial action. dunite An ultrabasic plutonic rock in which the mafic material is almost entirely olivine, with accessory chromite almost always present. Feldspar mainly plagioclase. See also peridotite. duricrust A general term for hard crust existing as a layer in or on the surface of the upper horizons of a soil in semi-arid climates. Duricrust is formed by the accumulation of solid minerals deposited by water moving upwards by capillary action and evaporating in the dry season. Compare


id: glossary-of-geology-20260505-4
file: data/en.wikipedia.org/wiki/Glossary_of_geology-4.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
fossil Any mineralized or otherwise preserved remains or traces (such as footprints) of animals, plants, or other once-living organisms. fossiliferous Bearing or being composed of fossils in rocks or strata. fossilization fracture Any crack or discontinuity. In its geological definition, it is only used when no displacement can be distinguished. fumarole A vent in the Earth's surface from which hot gases and vapors are emitted. == G == Ga A non-standard but widely used abbreviation for one billion (1,000,000,000) years, using the metric prefix G (for "Giga") to indicate a quantity of one billion. When not otherwise qualified, it usually indicates 1,000,000,000 years Before Present (or 1,000,000,000 years ago). gabbro A dark, coarse-grained, intrusive igneous rock chemically equivalent to basalt. garnet gastrolith A rock which is or was once held inside the digestive tract of a living animal. gemology Also spelled gemmology. The branch of geology and mineralogy that studies natural and artificial gemstones. gemstone Also called a gem, fine gem, jewel, precious stone, or semi-precious stone. geogenic Of geologic origin – Resulting from naturally occurring geological processes. geological map A special-purpose map made to show geological features. geological time scale Also geologic time scale. geology geosyncline A mobile down-warping


id: glossary-of-geology-20260505-5
file: data/en.wikipedia.org/wiki/Glossary_of_geology-5.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
joint A discrete discontinuity surface without evidence of displacement. See also diaclase or bedding. Jurassic A major unit of the geologic timescale that extended from about 199.6 ± 0.6 Ma (million years ago) to 145.4 ± 4.0 Ma, between the end of the Triassic and the beginning of the Cretaceous. == K == Ka A non-standard but widely used abbreviation for one thousand (1,000) years, using the metric prefix K (for "Kilo") to indicate a quantity of one thousand. When not otherwise qualified, it usually indicates 1,000 years Before Present (or 1,000 years ago). kame An irregularly shaped hill or mound composed of sand, gravel and till that accumulates in a depression on a retreating glacier and is then deposited on the land surface with further melting of the glacier. kaolinite A finely crystalline form of hydrated aluminium silicate occurring as minute monoclinic flaky crystals with a perfect basal cleavage, resulting mainly from the alteration of feldspars under conditions of hydrothermal or pneumatolytic metamorphism. karst A distinct type of landscape shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite. Karst topography is usually characterised by closed depressions or sinkholes,


id: glossary-of-geology-20260505-6
file: data/en.wikipedia.org/wiki/Glossary_of_geology-6.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
metasilicate A salt of the non-existing metasilicic acid H2SiO3 based on an analogy with the carbonate system. metatexis Low-grade anatexis: partial or differential melting of rock components with a low melting point. mica Any of a set of minerals which crystallise in the monoclinic system. They have similar chemical compositions and highly perfect basal cleavage. micropaleontology A branch of paleontology which studies microfossils. mid-oceanic ridge An underwater mountain range typically having a valley known as a rift running along its axis, formed by plate tectonics. migmatite A composite rock composed of igneous or igneous-looking and/or metamorphic materials which are generally distinguishable megascopically. mineral mineralization The hydrothermal deposition of economically important metals in the formation of ore bodies or "lodes". mineralogy miogeosyncline A geosyncline in which volcanism is not associated with sedimentation, or the non-volcanic part of the orthogeosyncline located near the craton. Mohs scale of mineral hardness Also simply called the Mohs scale. molasse A partly marine, partly continental or deltaic sedimentary facies consisting of a very thick sequence of soft ungraded cross-bedded fossiliferous conglomerates, sandstones, shales, and marls. molding The process of manufacturing by shaping pliable raw material using a rigid frame or model called a mold. montmorillonite Swelling


id: glossary-of-geology-20260505-7
file: data/en.wikipedia.org/wiki/Glossary_of_geology-7.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
phenoclast A large, conspicuous fragment in sediment or sedimentary rock composed of various sizes of material. phenocryst A relatively large crystal in an igneous rock. phyllite Any of a set of argillaceous rocks in a condition of metamorphism between slate and mica-schist. phyllonite A rock that macroscopically resembles phyllite but that is formed by mechanical degradation (mylonization) of initially coarser rocks (e.g., graywacke, granite, or gneiss). piercing point A feature that is cut by a fault and moved. Reconstruction of that object can show how much the fault has moved. pillar A vertical, standing, often spire-shaped, natural rock formation. pitchstone A black, opaque volcanic glass that may contain irregular, whitish clusters of minerals. Resembles pitch in appearance. plate tectonics The set of natural processes and phenomena which result in large-scale movements of portions of the Earth's lithosphere, which is fragmented into multiple tectonic plates of various sizes. Pleistocene The geologic epoch which lasted from about 2,588,000 to 11,700 years ago, spanning the world's recent period of repeated glaciations. The Pleistocene is the first epoch of the Quaternary Period and the sixth epoch of the Cenozoic Era. Pliocene The geologic period that extends from 5.332 million to 2.588[2] million years Before


id: glossary-of-geology-20260505-8
file: data/en.wikipedia.org/wiki/Glossary_of_geology-8.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
rudite A generic term for any of a set of sedimentary rocks composed of rounded or angular detrital grains, i.e. granules, pebbles, cobbles, and boulders, which are coarser than sand in size. == S == saccharoidal Having a texture similar to that of granulated sugar. Saldanian orogeny sand sandstone Sand (with grains up to 2 mm in diameter) in which the grains are cemented together by secondary silica or calcite. Sandstone may be loosely cemented and soft or well cemented and hard, and is usually buff to brownish in color, sometimes reddish, due to the presence of iron oxides, or greenish, due to the presence of glauconite. sanidine A form of potash feldspar identical in composition with orthoclase but physically different, formed under different conditions and occurring in different rock types. It is the high temperature form of orthoclase, into which it inverts at 900 °C (1,650 °F). Occurs in lavas and dyke rocks. schist A group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. In French, schist is understood as shale. scree See talus. sediment trap A depression in which sediments substantially accumulate over time. sedimentary


id: glossary-of-geology-20260505-9
file: data/en.wikipedia.org/wiki/Glossary_of_geology-9.md
category: reference
title: Glossary of geology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geology
date_saved: 2026-05-05T07:50:56.265417+00:00
instance: kb-cron
parent: glossary-of-geology-20260505-0
summary:
tempestite Storm deposits found in sedimentary formations where shell debris accumulate under the effect of waves and seawater movement. tenacity A mineral's behavior when deformed or broken. tephra Fragmental material produced by a volcanic eruption regardless of composition, fragment size or emplacement mechanism. Once clasts have fallen to the ground they remain as tephra unless hot enough to fuse together into pyroclastic rock or tuff. Tethys Ocean A prehistoric ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean. till Also called glacial till. Unsorted glacial sediment. Glacial drift is a general term for the coarsely graded and extremely heterogeneous sediments of glacial origin. Glacial till is that part of glacial drift which was deposited directly by the glacier. tillite A type of sedimentary rock derived from glacial till which has been indurated or lithified by subsequent burial into solid rock. titanite A calcium titanium nesosilicate mineral, CaTiSiO5. See also sphene. topography The arrangement of the natural and artificial physical features of an area. tor A large, free-standing residual mass (rock outcrop) that rises abruptly from the surrounding smooth and gentle slopes of a rounded hill summit or ridge


id: glossary-of-geothermal-heating-and-cooling-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling-0.md
category: reference
title: Glossary of geothermal heating and cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling
date_saved: 2026-05-05T07:50:57.485688+00:00
instance: kb-cron
parent: glossary-of-geothermal-heating-and-cooling-20260505-0
summary:
The Glossary of Geothermal Heating and Cooling provides definitions of many terms used within the Geothermal heat pump industry. The terms in this glossary may be used by industry professionals, for education materials, and by the general public. == A == === Active Borehole Length === The length of the U-bend in the borehole below the header trench (usually 4 to 6 feet less than the total borehole length from the surface). === Advanced Geothermal System (AGS) === See Closed-Loop Geothermal System entry. === Ambient Air === The surrounding air (usually outdoor air or the air in a specific location). === Ambient Ground Temperature === The natural temperature of the earth in a specific location. This temperature will typically be quite stable at a depth of 30' (9 m) and is usually close to the annual average air temperature of the area and is influenced primarily by the average air temperature and secondarily by the thermal energy absorbed from the sun. While the ambient ground temperature is constant, as heat is extracted or rejected via the ground heat exchanger (GHX), the temperature will vary. Typically, a GHX is designed to operate at a minimum fluid temperature of about 32°F (0°C)


id: glossary-of-geothermal-heating-and-cooling-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling-1.md
category: reference
title: Glossary of geothermal heating and cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling
date_saved: 2026-05-05T07:50:57.485688+00:00
instance: kb-cron
parent: glossary-of-geothermal-heating-and-cooling-20260505-0
summary:
=== Deep Earth Temperatures === Relatively constant temperature at a given depth which vary when heat is extracted or rejected by ground loops. === Degree Day === A measure of the severity and duration of an outdoor temperature deviation above or below a fixed temperature (65 F), used in estimating the heating or cooling requirement and fuel consumption of a building for either summer or winter conditions. === Delta P === Difference in pressure between two test points === Delta T === Temperature difference between two test sites such as supply and return air or entering and leaving water in ground loop. === Demand (DMD) === The electrical input required to operate a GSHP unit for space conditioning. === Design Loop Temperatures === Temperatures that the ground loop is designed to stay above during the heating mode and below during cooling mode. === Design Outdoor Temperature === Outdoor air temperatures that coincides with the peak seasonal heating or cooling load. === Design Loads === The peak heating or cooling load used to select the equipment for a system (such as a heat pump) and to design the air distribution system (supply air diffusers, return air grilles, and the duct system).


id: glossary-of-geothermal-heating-and-cooling-20260505-2
file: data/en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling-2.md
category: reference
title: Glossary of geothermal heating and cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling
date_saved: 2026-05-05T07:50:57.485688+00:00
instance: kb-cron
parent: glossary-of-geothermal-heating-and-cooling-20260505-0
summary:
=== Flow Center === A packaged set of circulating pumps mounted in a cabinet, which often includes valves and ports for flushing/purging, antifreeze charging (if used), and loop pressurization (if a pressurized flow center is used). === Flow Meter === A device that indicates water flow (often in gallons per minute) === Flow Rater === Component that reduces fluid flow to a specified rate (such as 4 gpm). === Fluid Factor === A factor, F, used in calculating geoexchange rate, G, in BTUs/hr. where ΔT is in °F and Q is gallons per minute. For water, F is approximately 500. For antifreeze solutions, F is approximately 485. === Flush Cart === A system which integrates the purge pump with the valving, hose connections, electrical connections, filtration, and reservoir tank on a hand cart for maximum portability and ease of use during operation. Flush carts fabricated for residential or light commercial use will typically utilize high-head, high-volume purge pumps from 1-1/2 hp to 3 hp in size. === Flow Regime === The nature of fluid flow in any situation. Flow regime can either be regarded as laminar, transitional, or turbulent. === Flushing Velocity === Velocity of fluid (often stated in feet/second)


id: glossary-of-geothermal-heating-and-cooling-20260505-3
file: data/en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling-3.md
category: reference
title: Glossary of geothermal heating and cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling
date_saved: 2026-05-05T07:50:57.485688+00:00
instance: kb-cron
parent: glossary-of-geothermal-heating-and-cooling-20260505-0
summary:
=== Heat of extraction (HE) === Thermal energy removed from the ground loop and provided to the building during heating mode. This is commonly referred to as geoexchange and is recognized as renewable thermal energy. Commonly expressed in BTU/hr === Heat of Extraction === The portion of a GSHP's heating capacity that is extracted from the earth in the heating mode. Heat of extraction is always smaller than the heating capacity of the heat pump because the electrical power consumption of the compressor, fan, and pumps add to the heating capacity of the GSHP. === Heat Fusion === Making a joint by heating the mating surfaces of the pipe components to be joined and pressing them together so that they fuse and become essentially one piece. === Heat Gain === When cooling a building the heat gain is the amount of btus a system must be able to reject elsewhere === Heat Load === Heat load is a calculation that identifies both the heat gain and the heat loss === Heat Loss === When heating a building the heat loss is the total number of btus that a system needs to extract from elsewhere or produce through combustion or resistance


id: glossary-of-geothermal-heating-and-cooling-20260505-4
file: data/en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling-4.md
category: reference
title: Glossary of geothermal heating and cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling
date_saved: 2026-05-05T07:50:57.485688+00:00
instance: kb-cron
parent: glossary-of-geothermal-heating-and-cooling-20260505-0
summary:
=== Monitoring System === Monitoring systems in the context of a geothermal system are used to monitor efficiency and operation. Some also give notices for maintenance such as filter changes and alerts for trouble such as excessive auxiliary use. This system could be linked to the internet for remote monitoring, could be in the form of an electric meter, an hour counter or a web based monitor or thermostat. === Multi-pipe Trench === A horizontal loop generally consisting of 2, 4 or 6 pipes. Pipes may be pinned to trench walls for separation or may have one course on the bottom of the trench and a second course after a foot or two of backfill. === Multi-source heat pump === A heat pump with access to more than one source/sink element of thermal energy. Common elements include, ground, solar, air, biomass, waste heat. Often applied with a thermal battery or thermal energy storage devices. == N == === Non-Pressurized Flow Center === A flow center that maintains a flow of water into the suction side of the pump (maintaining a flooded volute and reliable pump operation) by having the pump located directly adjacent to a column of water (in a


id: glossary-of-geothermal-heating-and-cooling-20260505-5
file: data/en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling-5.md
category: reference
title: Glossary of geothermal heating and cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling
date_saved: 2026-05-05T07:50:57.485688+00:00
instance: kb-cron
parent: glossary-of-geothermal-heating-and-cooling-20260505-0
summary:
=== Rule of Thumb === An estimate based on limited information. In geothermal "rules of thumb" are generally not considered best practice, especially not for sizing equipment or loopfields. === Run Fraction === The fraction of time that a GSHP system operates to condition a space for a given period of time, expressed as a decimal. === Run Time === The number of hours that a GSHP system operates to condition a space for a given period of time. == S == === Saturated Liquid === The temperature and pressure where refrigerant is all liquid, but will immediately begin to evaporate with addition of heat. === Saturated Vapor === The temperature and pressure where refrigerant is all vapor, but will immediately begin to condense with removal of heat. === Saturation Temperature === The temperature at which refrigerant will either immediately condense with the removal of heat (if in the vapor phase) or evaporate with the addition of heat (if in the liquid phase) at a given pressure. === Scaling === The build up of water impurities on the inside surface of the water-to-refrigerant heat exchanger in a GSHP, primarily caused by hardness and alkalinity of the water. This problem occurs


id: glossary-of-geothermal-heating-and-cooling-20260505-6
file: data/en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling-6.md
category: reference
title: Glossary of geothermal heating and cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_geothermal_heating_and_cooling
date_saved: 2026-05-05T07:50:57.485688+00:00
instance: kb-cron
parent: glossary-of-geothermal-heating-and-cooling-20260505-0
summary:
=== Thermal Conductivity Test === A thermal conductivity test measures the ability of the soil or rock a heat exchanger is buried in to transfer energy. To conduct a thermal conductivity test (TC test) of a vertical borehole, HDPE pipe is installed in a borehole to the depth that is most appropriate for the site and building loads. Heated water is circulated through the pipe. It is typically heated using electric elements powered by a generator. The flow rate and temperature of the water is measured as it enters and leaves the borehole. The test is typically operated for at least 48 hours. Flow rate and temperature data are recorded usually every 2 minutes. This is used to calculate the thermal properties of the borehole to determine how much heat can be rejected to or extracted from the borehole. This is used in conjunction with the building energy loads to calculate the number, spacing and depth of the boreholes for a proposed GCHP system. === Thermal Energy Storage === Tanks or devices used to store thermal energy. This can include tanks to store chilled water or ice (cold storage) or tanks used to store hot water or a variety of


id: glossary-of-pre-christian-lithuanian-names-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_pre-Christian_Lithuanian_names-0.md
category: reference
title: Glossary of pre-Christian Lithuanian names
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_pre-Christian_Lithuanian_names
date_saved: 2026-05-05T07:50:58.803312+00:00
instance: kb-cron
parent: glossary-of-pre-christian-lithuanian-names-20260505-0
summary:
A number of Lithuanian surnames evolved from the ancient pre-Christian Lithuanian personal names, such as Budrys, Girdenis, Tylenis, Vilkas, Amantas, Bukantas, Rimgaila, Vizgirda, Tarvydas. Many of them are of compound type, typically consisting of two stems (dithematic names), and many are of single stem. Sometimes the order of these stems may reverse, e.g., Norvaišas vs. Vaišnoras, Tautvydas vs. Vytautas. Some two-stemmed names have a clear etymology, arising from nicknames, such as Baltakis = Balt-akys = "White eyes". Alfred Senn suggests that such transparent names are less ancient development, while those with non-evident etymology originate from the Indo-European pra-language. A two-stemmed name may be further compounded into a patronymic cognomen/surname: Algirdas—Algirdaitis (son of Algirdas; see Lithuanian names of Vladimir Olgerdovich, Andrei of Polotsk, Dmitry of Bryansk), Žygimantas—Žygimantaitis. Much of this glossary of stems common in ancient Lithuanian names is based on Dictionary of Lithuanian Surnames, searchable online in the Lithuanian Surname Database (LSD). == A == Al-, Alg-; several suggested etymologies Algimantas, Algirdas, Almantas, Alminas, Alvydas Ar- Arminas, Arvydas Aš- lt:Ašmantas, Ašvydas == B == bu, but (may be first or second stem), associated with the verb "to be" (search for "Butautas" in the LSD) Butautas, Bukantas, Bukontas, Butigeidis, Butkintas/Butkus, Butnorius,


id: glossary-of-industrial-automation-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_industrial_automation-0.md
category: reference
title: Glossary of industrial automation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_industrial_automation
date_saved: 2026-05-05T07:51:01.435537+00:00
instance: kb-cron
parent: glossary-of-industrial-automation-20260505-0
summary:
This glossary of industrial automation is a list of definitions of terms and illustrations related specifically to the field of industrial automation. For a more general view on electric engineering, see Glossary of electrical and electronics engineering. For terms related to engineering in general, see Glossary of engineering. == A == abbreviated address callingCalling that enables a user to employ an address having fewer characters than the full address when initiating a call. absolute coordinatesThe absolute distances or angles that specify the position of a point with respect to the datum of a coordinate system. absolute coordinateOne of the coordinates that identify the position of an addressable point with respect to the origin of a specified coordinate system. absolute errorThe algebraic result of subtracting a true, specified or theoretically correct value from the computed, observed, measured or achieved value. absolute instructionA display command using absolute coordinates. absolute position sensorA sensor that gives directly the coordinate position of an element of a machine. absolute programmingProgramming using words indicating absolute dimensions (absolute coordinates). absolute vectorA vector whose start and end points are specified in absolute coordinates. accelerationRate of change of the velocity at the point under consideration per unit of time. accuracyA


id: glossary-of-industrial-automation-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_industrial_automation-1.md
category: reference
title: Glossary of industrial automation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_industrial_automation
date_saved: 2026-05-05T07:51:01.435537+00:00
instance: kb-cron
parent: glossary-of-industrial-automation-20260505-0
summary:
automatic modeThe operating mode in which the robot control system can operate in accordance with the task program. autcmatic mode of operationThe mode of operation of a numerically controlled machine in which it operates in accordance with the control data until stopped by the program or the operator. automationThe implementation of processes by automatic means. axis1. A direction in which a part of a robot can move in a linear or rotary mode. The number of axes is normally the number of guided and mutually independently driven links.2. A direction in which a part of a machine can move in a linear or rotary mode. == See also == Glossary of engineering Glossary of power electronics Glossary of civil engineering Glossary of mechanical engineering Glossary of structural engineering == Notes == == References == === Attribution === This article incorporates text from this source, which is in the public domain: IS 15571: Industrial automation glossary. New Delhi, Bureau of Indian Standards. 2005. == External links == === Websites === Glossary of Industrial Automation Automation Glossary of terms Glossary of technical terms commonly used by ABB An automation glossary Glossary - Industrial Electronic/Electrical Terms Robotics Glossary: a Guide to Terms and


id: glossary-of-levelling-terms-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_levelling_terms-0.md
category: reference
title: Glossary of levelling terms
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_levelling_terms
date_saved: 2026-05-05T07:51:02.734801+00:00
instance: kb-cron
parent: glossary-of-levelling-terms-20260505-0
summary:
This is a glossary of levelling terms. Levelling is a surveying method used to find relative height, one use of which is to ensure ground is level during construction, for example, when excavating to prepare for laying a foundation for a house. == Levelling terms == Automatic level – variant of the dumpy level, that makes use of a compensator that ensures that the line of sight remains horizontal once the operator has roughly leveled the instrument. The surveyor sets the instrument up quickly and doesn't have to relevel it carefully each time he sights on a rod on another point. It also reduces the effect of minor settling of the tripod. Three adjustment screws are used to level the instrument. Back sight (BS) – short for "back sight reading", the first staff reading taken by the surveyor after the levelling instrument is set up and levelled. B.S is generally taken on the point of known reduced level as on the benchmark or a change point. Benchmark (surveying) – fixed reference point of known elevation with respect to which RL of other points is determined. Benchmarks can be arbitrary or permanent, the former is used for calculation of reduced levels


id: glossary-of-library-and-information-science-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_library_and_information_science-0.md
category: reference
title: Glossary of library and information science
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_library_and_information_science
date_saved: 2026-05-05T07:51:04.073733+00:00
instance: kb-cron
parent: glossary-of-library-and-information-science-20260505-0
summary:
This glossary page is created to give readers a place to find key terms and concepts used in the Library and Information Science (LIS) field. There are a large range of topics including cataloging and organization, metadata, digital libraries, archival studies, and other areas covered. The purpose is to have one place with reliable sources for professionals in the field and students who are planning to go into it. This page is a glossary of library and information science. == A == Abstract Is a brief set of statements that summarize, classifies, evaluates, or describes the important points of a text, particularly a journal article. An abstract is typically found on the first page of a scholarly article. Because an abstract summarizes an article, it is very useful for either browsing or keyword searching. Annotation An explanatory or critical note or commentary. Annotation is also the process of adding an explanatory or critical note or commentary to a text. Reference lists are often annotated with comments about what each resource covered and how useful it was. Appendix A group of supplementary material appended to a text. It is usually related to the material in the main part of the text


id: glossary-of-library-and-information-science-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_library_and_information_science-1.md
category: reference
title: Glossary of library and information science
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_library_and_information_science
date_saved: 2026-05-05T07:51:04.073733+00:00
instance: kb-cron
parent: glossary-of-library-and-information-science-20260505-0
summary:
Cross reference database A collection of records that have one or more fields that reference other related records. These connections (for example between "marketing" and "promotion") make browsing very productive and allow related-items searches. == D == Database Is an organized collection of data, generally stored and accessed electronically from a computer system. Descriptor An index term used to identify a record in a database. It can consist of a word, phrase, or alphanumerical term. It can describe the content of the record or be an arbitrary code. When a descriptor is descriptive, it can be an effective search parameter. Dewey Decimal Classification (DDC) A hierarchical system for classifying books and other library materials by subject, first published in 1876 by the librarian and educator Melvil Dewey, who divided human knowledge into 10 main classes, each of which is divided into 10 divisions, etc. In Dewey Decimal call numbers, Arabic numerals and decimal fractions are used in the class notation (example: 996.9) and an alphanumeric book number is added to subarrange works of the same classification by author and by title and edition (996.9 B3262h). Digital preservation A formal process to ensure that digital information of continuing value remains accessible


id: glossary-of-library-and-information-science-20260505-2
file: data/en.wikipedia.org/wiki/Glossary_of_library_and_information_science-2.md
category: reference
title: Glossary of library and information science
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_library_and_information_science
date_saved: 2026-05-05T07:51:04.073733+00:00
instance: kb-cron
parent: glossary-of-library-and-information-science-20260505-0
summary:
Monograph A written document on a single subject, usually scholarly in nature and of approximately book length. They are valuable information sources because of their depth in a limited subject area. == O == OCLC (Online Computer Library Center) A comprehensive bibliographic network that provides bibliographic, abstract, and full-text information to users. Operators Symbols that represent operations. In computer science there are binary and unary operators depending on the number of elements or records an operator acts on. In database searching there are Boolean and Proximity operators. Boolean operators are a subclass of logical operators (Logical operators are binary operators that manipulate data at the bit level.). A Boolean operator manipulates the binary "true/false" value. Online catalog Or electronic catalog – a record of the holdings of an institution (e.g. library or museum) or group of institutions (a consortium), often searchable, that can be found on the Internet. Open access A mechanism by which research outputs are distributed online, free of cost or other barriers,[1] and, in its most precise meaning, with the addition of an open license applied to promote reuse. Open source In production and development a philosophy or methodology promoting free redistribution and access to an end


id: glossary-of-mechanical-engineering-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-0.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
Most of the terms listed in Wikipedia glossaries are already defined and explained within Wikipedia itself. However, glossaries like this one are useful for looking up, comparing and reviewing large numbers of terms together. You can help enhance this page by adding new terms or writing definitions for existing ones. This glossary of mechanical engineering terms pertains specifically to mechanical engineering and its sub-disciplines. For a broad overview of engineering, see glossary of engineering.


id: glossary-of-mechanical-engineering-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-1.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
== A == Abrasion – is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive. Abrasion can be an undesirable effect of exposure to normal use or exposure to the elements. Absolute zero – is the lowest possible temperature of a system, defined as zero kelvin or −273.15 °C. No experiment has yet measured a temperature of absolute zero. Accelerated life testing – is the process of testing a product by subjecting it to conditions (stress, strain, temperatures, voltage, vibration rate, pressure etc.) in excess of its normal service parameters in an effort to uncover faults and potential modes of failure in a short amount of time. By analyzing the product's response to such tests, engineers can make predictions about the service life and maintenance intervals of a product. Acceleration – In physics, acceleration is the rate of change of velocity of an object with respect to time. An object's acceleration is the net result of any and all forces acting on the object, as described by Newton's second law. The SI unit for acceleration is metre per second squared (m s−2). Accelerations are vector quantities


id: glossary-of-mechanical-engineering-20260505-2
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-2.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
The unifying abstract concept is that a certain amount of difference allows for some known factor of compensation or interference. For example, an area of excess metal may be left because it is needed to complete subsequent machining. Common cases are listed below. An allowance, which is a planned deviation from an ideal, is contrasted with a tolerance, which accounts for expected but unplanned deviations. American Society of Mechanical Engineers – The American Society of Mechanical Engineers (ASME) is a professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing education, training and professional development, codes and standards, research, conferences and publications, government relations, and other forms of outreach." Ampere – the base unit of electric current in the International System of Units (SI). It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics. Applied mechanics – describes the behavior of a body, in either a beginning state of rest or of motion, subjected to the action of forces. Applied mechanics, bridges the gap between physical theory and its application to technology. It is used in many fields of engineering,


id: glossary-of-mechanical-engineering-20260505-3
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-3.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
== B == Babbitt – also called Babbitt metal or bearing metal, is any of several alloys used for the bearing surface in a plain bearing. The original Babbitt alloy was invented in 1839 by Isaac Babbitt in Taunton, Massachusetts, United States. Backdrive – a component used in reverse to obtain its input from its output. This extends to many concepts and systems from thought based to practical mechanical applications. Backlash – sometimes called lash or play, is a clearance or lost motion in a mechanism caused by gaps between the parts. It can be defined as "the maximum distance or angle through which any part of a mechanical system may be moved in one direction without applying appreciable force or motion to the next part in mechanical sequence",p. 1-8. Balancing machine – a measuring tool used for balancing rotating machine parts such as rotors for electric motors, fans, turbines, disc brakes, disc drives, propellers and pumps. Ball detent – a simple mechanical arrangement used to hold a moving part in a temporarily fixed position relative to another part. Usually the moving parts slide with respect to each other, or one part rotates within the other. Ball screw – a


id: glossary-of-mechanical-engineering-20260505-4
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-4.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
Boiler – a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation.


id: glossary-of-mechanical-engineering-20260505-5
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-5.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
== C == CAD – see Computer-aided design. CAM – see Computer-aided manufacturing CAID – see Computer-aided industrial design. Calculator – An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics. Calculus – the mathematical study of continuous change. Car handling – Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, and braking as well as on the vehicle's directional stability when moving in steady state condition. Carbon fiber reinforced polymer – or carbon fiber reinforced plastic, or carbon fiber reinforced thermoplastic (CFRP, CRP, CFRTP, or often simply carbon fiber, carbon composite, or even carbon), is an extremely strong and light fiber-reinforced plastic which contains carbon fibers. Carbon fibers – or carbon fibres (alternatively CF, graphite fiber or graphite fibre) are fibers about 5–10 micrometres in diameter and composed mostly of carbon atoms. Carbon fibers have several advantages including high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and


id: glossary-of-mechanical-engineering-20260505-6
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-6.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
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parent: glossary-of-mechanical-engineering-20260505-0
summary:
+ y 2 H 2 O {\displaystyle {\ce {C_{\mathit {x}}H_{\mathit {y}}{}+{\mathit {z}}O2->{\mathit {x}}CO2{}+{\frac {\mathit {y}}{2}}H2O}}} , where z = x + y 4 {\displaystyle z=x+{\frac {y}{4}}} . Composite material – (also called a composition material, or shortened to composite), is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure, differentiating composites from mixtures and solid solutions. Compression ratio – The static compression ratio, (symbol ε {\displaystyle \varepsilon } ), of an internal combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity. It is a fundamental specification for many common combustion engines. Compressive strength – or compression strength, is the capacity of a material or structure to withstand loads tending to reduce size, as opposed to tensile strength, which withstands loads tending to elongate. In other words, compressive strength resists compression (being pushed together), whereas tensile strength resists tension (being pulled apart). In the study of strength of materials, tensile strength,


id: glossary-of-mechanical-engineering-20260505-7
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-7.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
== D == Damping ratio – an influence within or upon an oscillatory system that has the effect of reducing, restricting or preventing its oscillations. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples include viscous drag in mechanical systems, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Deformation (engineering) – refers to the change in size or shape of an object. Deformation that is reversible is termed as elastic deformation, while irreversible deformation is termed plastic deformation. Strain is the relative deformation of an infinitesimally small cube of material, and is generally linearly proportional to the forces or stresses acting on the cube while the deformation is elastic. The determination of the stress and strain throughout a solid object is given by the field of strength of materials and for a structure by structural analysis. Delamination – is a mode of failure where a material fractures into layers. A variety of materials including laminate composites and concrete can fail by delamination. Design – Design for manufacturability – (also sometimes known as design for manufacturing or DFM), is the general engineering practice of designing products in such


id: glossary-of-mechanical-engineering-20260505-8
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-8.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
== E == Elasticity – In physics, elasticity is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed. Solid objects will deform when adequate forces are applied to them. If the material is elastic, the object will return to its initial shape and size when these forces are removed. Hooke's law states that the force should be proportional to the extension. The physical reasons for elastic behavior can be quite different for different materials. In metals, the atomic lattice changes size and shape when forces are applied (energy is added to the system). When forces are removed, the lattice goes back to the original lower energy state. For rubbers and other polymers, elasticity is caused by the stretching of polymer chains when forces are applied. Electric current – a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. Electric motor – an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through


id: glossary-of-mechanical-engineering-20260505-9
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-9.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
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parent: glossary-of-mechanical-engineering-20260505-0
summary:
== G == Gas compressor – Gauge – Gear – a rotating circular machine part having cut or inserted teeth which mesh with another compatible toothed part to transmit torque and speed. Each gear tooth essentially functions as a lever with its fulcrum at the gear's center. Gear coupling – a mechanical device for transmitting torque between two shafts that are not collinear. It consists of a flexible joint fixed to each shaft. The two joints are connected by a third shaft, called the spindle. Gear ratio – the ratio of the pitch circles of mating gears which defines the speed ratio and the mechanical advantage of the gear set. Granular material – == H == Heat engine – a system that converts heat or thermal energy—and chemical energy—to mechanical energy, which can then be used to do mechanical work. Heat transfer – Heating and cooling systems – Hinge – Hoberman mechanism – Hobson's joint – Hooke's law – Hotchkiss drive – HVAC – Hydraulics – Hydrostatics – == I == Ideal machine – Ideal mechanical advantage – Imperial College London – Inclined plane – Independent suspension – Inductor – Industrial engineering – Inertia – Institution of Mechanical Engineers –


id: glossary-of-mechanical-engineering-20260505-10
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-10.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
== S == Safety engineering – Screw theory – Seal – Second law of thermodynamics – states that when energy changes from one form to another form, or matter moves freely, entropy (disorder) in a closed system increases. In other words, heat always moves from hotter objects to colder objects unless energy is supplied to reverse the direction of heat flow, and not all heat energy can be converted into work in a cyclic process. Semiconductor – Series and parallel circuits – Shear force diagrams – Shear pin – Shear strength – Shear stress – Simple machine – Simulation – Slide rule – Society of Automotive Engineers – Solid mechanics – Solid modeling – Split nut – Sprung mass – Statics – Steering – Stress–strain curve – a chart which gives the relationship between stress and strain for a given material. It is obtained by gradually applying load to a test coupon and measuring the deformation. Structural failure – Student Design Competition – Surveying – Suspension – Switch – an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. == T == Technical


id: glossary-of-mechanical-engineering-20260505-11
file: data/en.wikipedia.org/wiki/Glossary_of_mechanical_engineering-11.md
category: reference
title: Glossary of mechanical engineering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_mechanical_engineering
date_saved: 2026-05-05T07:51:05.490215+00:00
instance: kb-cron
parent: glossary-of-mechanical-engineering-20260505-0
summary:
== Y == Yield point – In materials science and engineering, the yield point is the point on a stress–strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible and is known as plastic deformation. Yield strength – or yield stress, is a material property and is the stress corresponding to the yield point at which the material begins to deform plastically. The yield strength is often used to determine the maximum allowable load in a mechanical component, since it represents the upper limit to forces that can be applied without producing permanent deformation. In some materials, such as aluminium, there is a gradual onset of non-linear behavior, making the precise yield point difficult to determine. In such a case, the offset yield point (or proof stress) is taken as the stress at which 0.2% plastic deformation occurs. Yielding is a gradual failure mode which is normally not catastrophic, unlike ultimate failure. Young's modulus – Young's modulus


id: glossary-of-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_medicine-0.md
category: reference
title: Glossary of medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_medicine
date_saved: 2026-05-05T07:51:06.887607+00:00
instance: kb-cron
parent: glossary-of-medicine-20260505-0
summary:
This glossary of medicine includes definitions of medical terminology and other terms pertaining to medicine and related fields.


id: glossary-of-medicine-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_medicine-1.md
category: reference
title: Glossary of medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_medicine
date_saved: 2026-05-05T07:51:06.887607+00:00
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parent: glossary-of-medicine-20260505-0
summary:
== A == Aarskog–Scott syndrome – (AAS) A rare, inherited (X-linked) disease characterized by short stature, facial abnormalities, skeletal and genital anomalies. Abdomen – The part of the body between the chest and pelvis, which contains most of the tubelike organs of the digestive tract, as well as several solid organs. Abdominal external oblique muscle – The largest, and outermost, of the three flat muscles of the lateral anterior abdominal wall. Abdominal internal oblique muscle – A muscle of the abdominal wall, which lies below the external oblique and just above the transverse abdominal muscles. Abductor pollicis brevis muscle – A muscle in the hand that abducts (straightens) the thumb. Abductor pollicis longus muscle – One of the extrinsic muscles of the hand. Its major function is to abduct the thumb at the wrist. Abscess – A collection of pus that has built up within the tissue of the body. Accommodation – the process by which the eye focuses on an object. Accommodation reflex – a reflex action of the eye, measured as a response to focusing on a near object, then looking at a distant object (and vice versa). Acetabulum – a concave surface of the pelvis, which forms


id: glossary-of-medicine-20260505-2
file: data/en.wikipedia.org/wiki/Glossary_of_medicine-2.md
category: reference
title: Glossary of medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_medicine
date_saved: 2026-05-05T07:51:06.887607+00:00
instance: kb-cron
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Most arteries carry oxygenated blood; the two exceptions are the pulmonary and the umbilical arteries, which carry deoxygenated blood to the organs that oxygenate it. The effective arterial blood volume is that extracellular fluid which fills the arterial system. Arthritis – is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. Asperger syndrome – (AS), also known as Asperger's, is a developmental disorder characterized by significant difficulties in social interaction and nonverbal communication, along with restricted and repetitive patterns of behavior and interests. As a milder autism spectrum disorder (ASD), it differs from other ASDs by relatively normal language and intelligence. Although not required for diagnosis, physical clumsiness and unusual use of language are common. Asthma – is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. Atony – absence of muscle tone. Atrial fibrillation – (AF or A-fib) is an abnormal heart rhythm characterized by rapid and


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title: Glossary of medicine
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== B == Back – The human back is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck and the shoulders. It is the surface of the body opposite from the chest. The vertebral column runs the length of the back and creates a central area of recession. The breadth of the back is created by the shoulders at the top and the pelvis at the bottom. Back pain – is pain felt in the back. It is divided into neck pain (cervical), middle back pain (thoracic), lower back pain (lumbar) or coccydynia (tailbone or sacral pain) based on the segment affected. The lumbar area is the most common area for pain, as it supports most of the weight in the upper body. Episodes of back pain may be acute, sub-acute, or chronic depending on the duration. The pain may be characterized as a dull ache, shooting or piercing pain, or a burning sensation. Discomfort can radiate into the arms and hands as well as the legs or feet, and may include numbness, or weakness in the legs and arms. Barotrauma – is injury caused by a pressure


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title: Glossary of medicine
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Bones support and protect the various organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have a complex internal and external structure. They are lightweight yet strong and hard, and serve multiple functions. Bone marrow – is a semi-solid tissue which may be found within the spongy or cancellous portions of bones. Bone marrow is the primary site of new blood cell production or hematopoiesis. It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adult humans, bone marrow is primarily located in the ribs, vertebrae, sternum, and bones of the pelvis. On average, bone marrow constitutes 4% of the total body mass of humans; in an adult having 65 kilograms of mass (143 lb), bone marrow typically accounts for approximately 2.6 kilograms (5.7 lb). Brachial artery – is the major blood vessel of the (upper) arm. It is the continuation of the axillary artery beyond the lower margin of teres major muscle. It continues down the ventral surface of the arm until it reaches the cubital fossa at the elbow. It then


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== C == Calcium – Calcium ions (Ca2+) contribute to the physiology and biochemistry of organisms and the cell. They play an important role in signal transduction pathways, where they act as a second messenger, in neurotransmitter release from neurons, in contraction of all muscle cell types, and in fertilization. Many enzymes require calcium ions as a cofactor, those of the blood-clotting cascade being notable examples. Extracellular calcium is also important for maintaining the potential difference across excitable cell membranes, as well as proper bone formation. Calf – is the back portion of the lower leg in human anatomy. The muscles within the calf correspond to the posterior compartment of the leg. The two largest muscles within this compartment are known together as the calf muscle and attach to the heel via the Achilles tendon. Several other, smaller muscles attach to the knee, the ankle, and via long tendons to the toes. Cancer – is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread to other parts of the body. Capillary – is a small blood vessel from 5


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title: Glossary of medicine
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Cell biology is concerned with the physiological properties, metabolic processes, signaling pathways, life cycle, chemical composition and interactions of the cell with their environment. Central nervous system – (CNS), is the part of the nervous system consisting of the brain and spinal cord. Cephalic vein – is a superficial vein in the arm. It communicates with the basilic vein via the median cubital vein at the elbow and is located in the superficial fascia along the anterolateral surface of the biceps brachii muscle. Near the shoulder, the cephalic vein passes between the deltoid and pectoralis major muscles (deltopectoral groove) and through the deltopectoral triangle, where it empties into the axillary vein. Cerebellum – (Latin for "little brain"), is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebellum plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language as well as in regulating fear and pleasure responses, but its movement-related functions are the most solidly established. The human cerebellum does not initiate movement,


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title: Glossary of medicine
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The throat, sinuses, and larynx may also be affected. Signs and symptoms may appear less than two days after exposure to the virus. These may include coughing, sore throat, runny nose, sneezing, headache, and fever. People usually recover in seven to ten days, but some symptoms may last up to three weeks. Occasionally, those with other health problems may develop pneumonia. Common iliac artery – The common iliac arteries are two large arteries that originate from the aortic bifurcation at the level of the fourth lumbar vertebra. They end in front of the sacroiliac joint, one on either side, and each bifurcates into the external and internal iliac arteries. Common iliac vein – The common iliac veins are formed by the external iliac veins and internal iliac veins. The left and right common iliac veins come together in the abdomen at the level of the fifth lumbar vertebra, forming the inferior vena cava. They drain blood from the pelvis and lower limbs. Both common iliac veins are accompanied along their course by common iliac arteries. Coronary arteries – are the blood vessels (arteries) of coronary circulation, which transports oxygenated blood to the actual heart muscle. The heart requires a continuous


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== D == Decompression sickness – is a condition caused by inert gas bubbles forming in supersaturated tissues after a reduction in ambient pressure, and either obstructing perfusion or causing local damage. Deep circumflex iliac vein – is formed by the union of the venae comitantes of the deep iliac circumflex artery, and joins the external iliac vein about 2 cm. above the inguinal ligament. It also receives small tributary branches from the thoracoepigastric vein Deep temporal arteries – The deep temporal arteries, two in number, anterior and posterior, ascend between the temporalis and the pericranium. They supply the muscle, and anastomose with the middle temporal artery. The anterior communicates with the lacrimal artery by means of small branches which perforate the zygomatic bone and great wing of the sphenoid. Definitive treatment – Medical treatment generally accepted as most appropriate for the condition. Deltoid muscle – is the muscle forming the rounded contour of the human shoulder. Anatomically, it appears to be made up of three distinct sets of fibers though electromyography suggests that it consists of at least seven groups that can be independently coordinated by the nervous system. Dentistry – also known as Dental and Oral Medicine, is


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== E == Ear – is the organ of hearing and, in mammals, balance. In mammals, the ear is usually described as having three parts—the outer ear, the middle ear and the inner ear. The outer ear consists of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. The ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localisation. Ear infection – Otitis is a general term for inflammation or infection of the ear, in both humans and other animals. It is subdivided into the following: Otitis externa, external otitis, or "swimmer's ear", involves the outer ear and ear canal. In external otitis, the ear hurts when touched or pulled. Otitis media, or middle ear


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title: Glossary of medicine
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External iliac artery – The external iliac arteries are two major arteries which bifurcate off the common iliac arteries anterior to the sacroiliac joint of the pelvis. External iliac vein – The external iliac veins are large veins that connect the femoral veins to the common iliac veins. Their origin is at the inferior margin of the inguinal ligaments and they terminate when they join the internal iliac veins (to form the common iliac veins). Both external iliac veins are accompanied along their course by external iliac arteries. External jugular vein – receives the greater part of the blood from the exterior of the cranium and the deep parts of the face, being formed by the junction of the posterior division of the retromandibular vein with the posterior auricular vein. Eye – The human eye is a sense organ that reacts to light and allows vision. Rod and cone cells in the retina are photoreceptive cells which are able to detect visible light and convey this information to the brain. Eyes signal information which is used by the brain to elicit the perception of color, shape, depth, movement, and other features. The eye is part of the sensory nervous system.


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title: Glossary of medicine
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== F == Face – is the front of an animal's head that features three of the head's sense organs, the eyes, nose, and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities affects the psyche adversely. Fallopian tube – The fallopian tubes, also known as uterine tubes or salpinges (singular salpinx), are tubes that stretch from the uterus to the ovaries, and are part of the female reproductive system. The fertilized egg passes through the fallopian tubes from the ovaries of female mammals to the uterus. The fallopian tube is simple columnar epithelium with hair-like extensions called cilia which carry the fertilized egg. In other animals, the equivalent of a fallopian tube is an oviduct. Fellowship (medicine) – is the period of medical training, in the United States and Canada, that a physician, dentist, or veterinarian may undertake after completing a specialty training program (residency). During this time (usually more than one year), the physician is known as a fellow. Fellows are capable of acting as an attending physician or a consultant physician in the specialist field in which they were trained, such


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title: Glossary of medicine
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It originates from the galea aponeurotica and inserts into the skin of the eyebrows, playing a key role in facial expressions by raising the eyebrows and wrinkling the forehead. Innervated by the temporal branch of the facial nerve (cranial nerve VII), it helps convey emotions like surprise or concern. Its activity is also relevant in clinical conditions such as Bell's palsy and cosmetic procedures like Botox, which target its function to reduce forehead lines.


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== G == Gallbladder – In vertebrates, the gallbladder is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although the structure and position of the gallbladder can vary significantly among animal species. It receives and stores bile, produced by the liver, via the common hepatic duct and releases it via the common bile duct into the duodenum, where the bile helps in the digestion of fats. Gamete – is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. Ganglion – is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympathetic and parasympathetic ganglia which contain the cell bodies of postganglionic sympathetic and parasympathetic neurons respectively. Gastrocnemius muscle – (plural gastrocnemii) is a superficial two-headed muscle that is in the back part of the lower leg of humans. It runs from its two heads just


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title: Glossary of medicine
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== H == Hand – A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates. The human hand normally has five digits: four fingers plus one thumb; these are often referred to collectively as five fingers, however, whereby the thumb is included as one of the fingers. It has 27 bones, not including sesmoid bones, the number of which varies between people, 14 of which are the phalanges (proximal, intermediate and distal) of the fingers and thumb. The metacarpal bones connect the fingers and the carpal bones of the wrist. Each human hand has five metacarpals and eight carpal bones. Hand surgery – deals with both surgical and non-surgical treatment of conditions and problems that may take place in the hand or upper extremity (commonly from the tip of the hand to the shoulder) including injury and infection. Hand surgery may be practiced by graduates of general surgery, orthopedic surgery and plastic surgery. Chiroplasty, or cheiroplasty, is plastic surgery of the hands. Head – In human anatomy, the head is at the top of the human body. It supports the face and is maintained by the skull, which itself encloses the brain.


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== I == Iliac artery, common – The common iliac arteries are two large arteries that originate from the aortic bifurcation at the level of the fourth lumbar vertebra. They end in front of the sacroiliac joint, one on either side, and each bifurcates into the external and internal iliac arteries. Iliac artery, external – The external iliac arteries are two major arteries which bifurcate off the common iliac arteries anterior to the sacroiliac joint of the pelvis. They proceed anterior and inferior along the medial border of the psoas major muscles. They exit the pelvic girdle posterior and inferior to the inguinal ligament about one third laterally from the insertion point of the inguinal ligament on the pubic tubercle at which point they are referred to as the femoral arteries. The external iliac artery is usually the artery used to attach the renal artery to the recipient of a kidney transplant. Ilium – (plural ilia), is the uppermost and largest part of the hip bone, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an


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title: Glossary of medicine
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== K == Keratogenesis– The production of horny cells in the epidermis. Keratopathy- Kidney – The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about 12 centimetres (4+1⁄2 inches) in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder. Knee – In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis. Korsakoff syndrome- (KS) is an amnestic disorder caused by thiamine (vitamin B1) deficiency typically associated with prolonged use of alcohol. The syndrome and psychosis are named after Sergei Korsakoff, the Russian neuropsychiatrist who discovered it during the late 19th century. This neurological


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title: Glossary of medicine
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== M == Major depressive disorder – (MDD), also known simply as depression, is a mental disorder characterized by at least two weeks of pervasive low mood. Low self-esteem, loss of interest in normally enjoyable activities, low energy, and pain without a clear cause are common symptoms. Those affected may also occasionally have delusions or hallucinations. Some people have periods of depression separated by years, while others nearly always have symptoms present. Major depression is more severe and lasts longer than sadness, which is a normal part of life. Male reproductive system – Mammary gland – Mandible – The mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human face. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear). Masseter muscle – In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it is the most superficial and one of the


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== N == Nail – A nail is a claw-like keratinous plate at the tip of the fingers and toes in most primates. Nails correspond to claws found in other animals. Fingernails and toenails are made of a tough protective protein called alpha-keratin which is found in the hooves, hair, claws and horns of vertebrates. Nanobiotechnology – Nanobiotechnology, bionanotechnology, and nanobiology are terms that refer to the intersection of nanotechnology and biology. Given that the subject is one that has only emerged very recently, bionanotechnology and nanobiotechnology serve as blanket terms for various related technologies. Nasal cavity – is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nasal cavity is the uppermost part of the respiratory system and provides the nasal passage for inhaled air from the nostrils to the nasopharynx and rest of the respiratory tract. The paranasal sinuses surround and drain into the nasal cavity. Nasopharynx – The upper portion of the pharynx, the nasopharynx, extends from the base of the skull to the upper surface


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== O == Oblique muscle of auricle – The oblique muscle of auricle (oblique auricular muscle or Tod muscle) is an intrinsic muscle of the outer ear. The oblique muscle of auricle is placed on the cranial surface of the pinna. It consists of a few fibers extending from the upper and back part of the concha to the convexity immediately above it. Obstetrics – is the field of study concentrated on pregnancy, childbirth and the postpartum period. As a medical specialty, obstetrics is combined with gynecology under the discipline known as obstetrics and gynecology (OB/GYN), which is a surgical field. Obstetrics and gynaecology – Obstetrics and gynaecology (British English) or obstetrics and gynecology (American English) is the medical specialty that encompasses the two subspecialties of obstetrics (covering pregnancy, childbirth, and the postpartum period) and gynecology (covering the health of the female reproductive system – vagina, uterus, ovaries, and breasts). It is commonly abbreviated as OB-GYN or OB/GYN in US English, and as obs and gynae or O&G in British English. Occipital bone – is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved


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title: Glossary of medicine
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== P == Palate – is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly separated. The palate is divided into two parts, the anterior, bony hard palate and the posterior, fleshy soft palate (or velum). Palliative care – (derived from the Latin root palliare, or "to cloak") is an interdisciplinary medical caregiving approach aimed at optimizing quality of life and mitigating suffering among people with serious, complex illness. Within the published literature, many definitions of palliative care exist; most notably, the World Health Organization describes palliative care as "an approach that improves the quality of life of patients and their families facing the problems associated with life-threatening illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems, physical, psychosocial, and spiritual." In the past, palliative care was a disease specific approach, but today the World Health Organization takes a more broad approach, that the principles of palliative care should be applied as early as possible to


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== R == Radial artery – In human anatomy, the radial artery is the main artery of the lateral aspect of the forearm. Radial nerve – is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial compartment of the forearm and the associated joints and overlying skin. It originates from the brachial plexus, carrying fibers from the ventral roots of spinal nerves C5, C6, C7, C8 & T1. Radiology – is the medical discipline that uses medical imaging to diagnose and treat diseases within the body. Radius – The radius, or radial bone, is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is usually slightly longer than the radius, but the radius is thicker. Therefore, the radius is considered to be the larger of the two. It is a long bone, prism-shaped and slightly curved longitudinally. Rectum – is


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== T == Tarsus – In the human body, the tarsus is a cluster of seven articulating bones in each foot situated between the lower end of the tibia and the fibula of the lower leg and the metatarsus. It is made up of the midfoot (cuboid, medial, intermediate, and lateral cuneiform, and navicular) and hindfoot (talus and calcaneus). Taste – The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, mostly on the tongue. Taste, along with smell (olfaction) and trigeminal nerve stimulation (registering texture, pain, and temperature), determines flavors of food and other substances. Humans have taste receptors on taste buds and other areas including the upper surface of the tongue and the epiglottis. The gustatory cortex is responsible for the perception of taste. Teeth – Temple – Temporal arteries, deep – Temporal artery, middle – Temporal artery, superficial – Temporal muscle – Tendon – Tensor fasciae latae muscle – Testicle – Thigh – Thoracic diaphragm – Thorax – Throat


id: glossary-of-medicine-20260505-23
file: data/en.wikipedia.org/wiki/Glossary_of_medicine-23.md
category: reference
title: Glossary of medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_medicine
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== U == Ulna – is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. It runs parallel to the radius, the other long bone in the forearm. The ulna is usually slightly longer than the radius, but the radius is thicker. Therefore, the radius is considered to be the larger of the two. Ulnar artery – is the main blood vessel, with oxygenated blood, of the medial aspects of the forearm. It arises from the brachial artery and terminates in the superficial palmar arch, which joins with the superficial branch of the radial artery. It is palpable on the anterior and medial aspect of the wrist. Ulnar nerve – In human anatomy, the ulnar nerve is a nerve that runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is common. This nerve is directly connected to the little finger, and the adjacent half of the ring finger, innervating the palmar aspect of


id: glossary-of-medicine-20260505-24
file: data/en.wikipedia.org/wiki/Glossary_of_medicine-24.md
category: reference
title: Glossary of medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_medicine
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== V == Vaccine – is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future. Vaccines can be prophylactic (to prevent or ameliorate the effects of a future infection by a natural or "wild" pathogen), or therapeutic (e.g., vaccines against cancer, which are being investigated). Vagina – In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vulva to the cervix. The outer vaginal opening is normally partly covered by a membrane called the hymen. At the deep end, the cervix (neck of the uterus) bulges into the vagina. The vagina allows for sexual intercourse and birth. It also channels menstrual flow (menses), which occurs in humans and closely related primates as part of the monthly menstrual cycle. Vas


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file: data/en.wikipedia.org/wiki/Glossary_of_medicine-25.md
category: reference
title: Glossary of medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_medicine
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== W == Waist – is the part of the abdomen between the rib cage and hips. On people with slim bodies, the waist is the narrowest part of the torso. The waistline refers to the horizontal line where the waist is narrowest, or to the general appearance of the waist. Wart – Warts are typically small, rough, hard growths that are similar in color to the rest of the skin. They typically do not result in other symptoms, except when on the bottom of the feet, where they may be painful. While they usually occur on the hands and feet, they can also affect other locations. One or many warts may appear. They are not cancerous. Weber test – is a screening test for hearing performed with a tuning fork. It can detect unilateral (one-sided) conductive hearing loss (middle ear hearing loss) and unilateral sensorineural hearing loss (inner ear hearing loss). The test is named after Ernst Heinrich Weber (1795–1878). Conductive hearing ability is mediated by the middle ear composed of the ossicles: the malleus, the incus, and the stapes. Sensorineural hearing ability is mediated by the inner ear composed of the cochlea with its internal basilar membrane and


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file: data/en.wikipedia.org/wiki/Glossary_of_medicine-26.md
category: reference
title: Glossary of medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_medicine
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== Y == Yaws – is a tropical infection of the skin, bones and joints caused by the spirochete bacterium Treponema pallidum pertenue. The disease begins with a round, hard swelling of the skin, 2 to 5 centimeters in diameter. The center may break open and form an ulcer. This initial skin lesion typically heals after three to six months. After weeks to years, joints and bones may become painful, fatigue may develop, and new skin lesions may appear. The skin of the palms of the hands and the soles of the feet may become thick and break open. The bones (especially those of the nose) may become misshapen. After five years or more large areas of skin may die, leaving a scar. Yellow fever – is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains particularly in the back, and headaches. Symptoms typically improve within five days. In about 15% of people, within a day of improving the fever comes back, abdominal pain occurs, and liver damage begins causing yellow skin. If this occurs, the risk of bleeding and kidney problems is increased. == Z == Zellweger spectrum


id: glossary-of-meteoritics-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_meteoritics-0.md
category: reference
title: Glossary of meteoritics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteoritics
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This is a glossary of terms used in meteoritics, the science of meteorites. == # == 2 Pallas – an asteroid from the asteroid belt and one of the likely parent bodies of the CR meteorites. 4 Vesta – second-largest asteroid in the asteroid belt and likely source of the HED meteorites. 221 Eos – an asteroid from the asteroid belt and one of the likely parent bodies of the CO meteorites. 289 Nenetta – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites. 3103 Eger – an asteroid from the asteroid belt and one of the likely parent bodies of the aubrites. 3819 Robinson – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites. IA meteorite – an iron meteorite group now part of the IAB group/complex. IAB meteorite – an iron meteorite and primitive achondrite of the IAB group/complex. IB meteorite – an iron meteorite group now part of the IAB group/complex. IC meteorite – an iron meteorite that is part of the IC group. == A == Ablation – the process of a meteorite losing mass during the passage through the atmosphere. Acapulcoite


id: glossary-of-meteoritics-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_meteoritics-1.md
category: reference
title: Glossary of meteoritics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteoritics
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== I == Impact breccia – rock composed of fragments of terrestrial, extraterrestrial or mixed origin fused by the energy of impact Impactite – informal term for a terrestrial rock resulting from the shocking impact of a meteor. Insoluble organic matter – Kerogen-like macromolecule residue from carbonaceous chondrite meteorites after soluble organic matter has been removed. Iron–nickel alloy – an alternative expression for meteoric iron. Iron meteorite – a meteorite that is mainly composed of meteoric iron. == K == Kakangari chondrite – a group of chondrite meteorites. Kamacite – a native metal (mineral) found in meteorites. == L == Lodranite – member of a small group of primitive achondrites thought to derive from deeper within the same parent body as acapulcoites Lunaite – a meteorite that originated from the Moon (synonym of Lunar meteorite). Compare Category:Meteorites found on bodies other than Earth. Lunar meteorite – a meteorite that originated from the Moon (synonym of Lunaite). Compare Category:Meteorites found on bodies other than Earth. == M == Main group pallasite – a pallasite belonging to the main group. Main mass – the largest/heaviest piece of a fragmented meteorite, typically found in a strewn field. Magmatic meteorite Martian meteorite – a


id: glossary-of-meteorology-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-0.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
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This glossary of meteorology is a list of terms and concepts relevant to meteorology and atmospheric science, their sub-disciplines, and related fields. == 0–9 == 2 meter temperature Temperature value at 2 meters above the ground, calculated rather than directly observed. Also written as 2t, 2m temperature, T2m, or with "metre" == A == advection The horizontal transport of some property of the atmosphere or ocean, such as thermal energy, humidity, or salinity. In the context of meteorology, the related term convection generally refers to vertical transport. actinoform Also actiniform. Describing a collection of low-lying, radially structured clouds with distinct shapes (resembling leaves or wheels in satellite imagery), and typically organized in extensive mesoscale fields over marine environments. They are closely related to and sometimes considered a variant of stratocumulus clouds. actinometer A scientific instrument used to measure the heating power of radiation, particularly solar radiation. active surface That part of the Earth's surface which is in direct contact with the atmosphere and which undergoes the greatest diurnal temperature changes, absorbing heat during the day and radiating it to the atmosphere at night. Examples include bare soil, the canopy of a forest, and the uppermost surface waters of the ocean.


id: glossary-of-meteorology-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-1.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
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anticyclone Any large-scale air mass characterized by outward spiraling winds which circulate around a strong center of high atmospheric pressure. Surface-based anticyclones generally bring about cool, dry air and clear skies and are often implicated in weather phenomena such as fog and haze. Contrast cyclone. anticyclonic rotation anticyclonic storm Any storm system involving an anticyclone, in which winds circulate around a region of high pressure in the direction opposite to that expected around a region of low pressure. Anticyclonic storms rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. anticyclonic tornado anticyclogenesis The development or strengthening of an anticyclonic circulation in the atmosphere, which may result in the formation or maintenance of a high-pressure area. Contrast cyclogenesis. antitriptic wind A wind generated by the local topography of a particular place; examples include anabatic winds and katabatic winds. Most such winds are diurnal in character. Anvil The top of a cumulonimbus (Cb) is often flat and spreading, shaped like an anvil. Thunderstorm anvils are capable of spreading great distances away from the thunderstorm itself. apparent temperature See heat index. arcus cloud Arctic cyclone Atlantic hurricane A tropical cyclone (locally known as a hurricane) that forms in the Atlantic


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-2.md
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title: Glossary of meteorology
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baroclinity Also baroclinicity. A measure of the misalignment between a pressure gradient and a density gradient in a stratified fluid such as the atmosphere. In the context of meteorology, a baroclinic atmosphere is one in which atmospheric density depends on both temperature and pressure, in contrast to a barotropic atmosphere, in which density depends only on pressure. Areas of high atmospheric baroclinity are generally found in the temperate and polar latitudes and are characterized by the frequent formation of cyclones. barotropity Also barotropicity. The close alignment between a pressure gradient and a density gradient in a stratified fluid such as the atmosphere. In the context of meteorology, a barotropic atmosphere is one in which atmospheric density depends only on pressure and is more or less independent of temperature, in contrast to a baroclinic atmosphere. Unlike liquids, gaseous fluids such as the air in the atmosphere are generally not barotropic, but the assumption of barotropity can nonetheless be useful in modeling fluid behavior. Tropical latitudes are more nearly barotropic than the mid-latitudes because air temperature is more nearly horizontally uniform in the tropics. barometer A scientific instrument used to measure atmospheric pressure. The two most common types are mercury barometers and


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-3.md
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title: Glossary of meteorology
tags: science, encyclopedia
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catabatic wind See katabatic wind. ceiling A measure of the height above the Earth's surface of the base of the lowest layer of clouds or obscuring phenomena that covers more than half of the sky (more than four oktas). An "unlimited" ceiling means either that the sky is mostly free of cloud cover or that the clouds are sufficiently high so as not to impede aircraft operation by visual flight rules. ceiling balloon Also pilot balloon or pibal. A type of weather balloon used by meteorologists to determine the height of the cloud base above ground level during daylight hours by measuring the time it takes for the balloon, released from the ground and rising at a known rate of ascent, to begin to disappear into the clouds. ceiling projector A type of cloud-height indicator that uses a searchlight to project a beam of light vertically onto a cloud base (similar to a ceilometer), with the height of the illuminated spot then calculated by the observer using a clinometer or alidade. ceilometer An instrument that uses a laser transmitter or other light source and a collocated receiver to determine the height of a cloud ceiling or cloud base overhead, or


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-4.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
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cloud An aerosol consisting of a visible mass of minute liquid droplets, frozen crystals or other particles suspended in the atmosphere. Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of the saturation of an air mass when it is cooled to its dew point or when it gains sufficient moisture (usually in the form of water vapor) from an adjacent source to raise the dew point to the ambient temperature. There are many different types of clouds, which are classified and named according to their shape and altitude. cloud atlas A pictorial key to the classification and nomenclature of clouds. cloud base The lowest altitude of the visible portion of a cloud. cloud bow See fogbow. cloud cover The obscuration of all or part of the sky by clouds as observed from a particular location, or the specific fraction of the sky obscured by clouds as measured in oktas. cloud drop effective radius cloud genus See cloud type. cloud iridescence Also irisation. A type of photometeor consisting of colorful iridescent patterns appearing most commonly near the semi-transparent edges of thin clouds such as cirrus and altocumulus that are in


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-5.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
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corona An optical phenomenon consisting of apparent concentric, pastel-colored rings around a bright celestial object (such as the Sun or the Moon), which are produced by the diffraction of light by individual water droplets or sometimes small ice crystals in a cloud or on a foggy glass surface. Coronae differ from halos in that the latter are formed by refraction from comparatively large particles. crepuscular rays crosswind Any wind that moves in a direction that is perpendicular to the direction of travel of a reference object, such as an airplane. Crow instability Also vortex Crow instability. An inviscid line-vortex instability most commonly observed in the skies behind large aircraft such as the Boeing 747. It occurs when the wingtip vortices interact with contrails from the engines, producing characteristic visual distortions in the shapes of the contrails. cumuliform Of or relating to heaped, "puffy" clouds, such as cumulus or cumulonimbus, that form as a result of atmospheric convection. cumulonimbus cumulus (Cu) A genus of cloud characterized by low-level "puffy" or "cotton-like" forms with flat bases (generally opaque white in color but sometimes with grey undersides), which occur individually or multiply in a variety of distinct subforms, usually at altitudes less than


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-6.md
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title: Glossary of meteorology
tags: science, encyclopedia
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diabatic process Also non-adiabatic process. Any thermodynamic process in which the temperature of an air parcel changes as a result of the transfer of energy (e.g. heat) between the parcel and its surroundings, as opposed to an adiabatic process, in which the temperature changes without any such exchange. Most thermodynamic processes near the Earth's surface are diabatic, owing to the continual mixing of air and turbulence. Diablo wind diamond dust A ground-level cloud composed of tiny ice crystals. Because it generally forms in sub-freezing temperatures beneath otherwise clear or nearly clear skies, diamond dust is sometimes referred to as clear-sky precipitation. diffluence The elongation of a fluid body, such as an air mass, normal to the flow (streamline divergence). It is a flow pattern of deformation. diffuse sky radiation Also simply diffuse radiation. The component of incoming solar radiation that is scattered from the direct solar beam by molecules of air, aerosols, clouds, or particulate matter in the atmosphere and subsequently reaches the Earth's surface in nearly equal amounts from nearly all parts of the sky during daylight. direct circulation A closed, vertically distributed thermal circulation in the atmosphere, in which warm, lighter air rises and cold, denser air sinks


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-7.md
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title: Glossary of meteorology
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dust storm Also duster or duststorm. A meteorological phenomenon characterized by very strong winds that blow dust-filled air over an extensive area. Dust storms arise when a gust front or other strong wind blows loose dirt, sand, and/or small rocks from a dry surface into the atmosphere, drastically reducing visibility. Though the term is sometimes restricted to storms occurring over normally arable land suffering from drought, it is also used interchangeably with sandstorm and haboob. == E == echo On a radar display, the appearance of the radio signal that is scattered or reflected back from a target. The distinct characteristics of a radar echo can be used to identify the distance and velocity of the target with respect to the signal source as well as the target's size, shape, and composition. eddy The swirling motion of a fluid and the reverse current created when the flow regime experiences turbulence, such as when an obstacle blocks part of the path of flow. Ekman layer The layer in a fluid in which there is a force balance between the pressure-gradient force, the Coriolis force, and turbulent drag. Ekman layers occur in both the atmosphere and the ocean. Ekman number Ekman spiral


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-8.md
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title: Glossary of meteorology
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fetch Also fetch length. The length of water over which a given wind blows. Fetch length and wind speed together determine the size of the waves that form on the surface of a body of water; the longer the fetch and the stronger the wind, the more wind energy is imparted to the water surface and the larger the resulting sea state. field mill A scientific instrument used to measure the strength of electric fields in the atmosphere. fire whirl Also fire devil and fire tornado. A whirlwind induced by a fire and often at least partially composed of flame or ash. They are usually associated with very large wildfires. Fire whirls are seldom classified as true tornadoes, as their vorticity usually derives from turbulent surface winds and heat-induced lifting rather than from a tornadic mesocyclone aloft. firestorm A very large wildfire or other conflagration which because of its intensity is able to create and sustain its own storm-force winds. Firestorms develop when a convective updraft of hot air rising from the burning area draws in strong wind gusts from all directions, which supply the fire with additional oxygen and thereby induce further combustion. They are often associated with flammagenitus


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-9.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
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frost A very thin layer of ice crystals on a solid surface, typically restricted to that which forms when water vapor in an atmosphere whose temperature is above freezing comes into contact with a surface whose temperature is below freezing. Frost may exhibit a great variety of forms. Fujita scale Also simply called the F scale. funnel cloud A funnel-shaped cloud associated with a rotating column of air and protruding from the base of a parent cloud but not reaching the ground or a water surface. Funnel clouds form most frequently in association with supercell thunderstorms and often develop into tornadoes. == G == gale 1. A strong surface wind, typically used as a descriptor in nautical contexts and variously defined based on speed. In the modern Beaufort scale, a gale is any sustained wind of Beaufort number 7 or greater, corresponding to near gale at 28–33 kn (52–61 km/h; 32–38 mph); gale at 34–40 kn (63–74 km/h); strong gale at 41–47 kn (76–87 km/h); and storm at 48–55 kn (89–102 km/h). 2. Any unusually strong wind. gale warning gap wind A local, low-level wind that blows along a valley or through a col between mountains, often at speeds as


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-10.md
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title: Glossary of meteorology
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haze Any suspension in the atmosphere of very small, dry particulate matter, including natural aerosols (e.g. dust, salt, or smoke) as well as man-made pollutants (e.g. smog), the individual particles of which are invisible to the naked eye but collectively produce a milky, often opalescent sky with reduced visibility at long distances. Haze usually indicates sub-saturated air, whereas fog or mist indicates full saturation. hazardous seas warning hazardous seas watch heat dome The effect created by Earth's atmosphere trapping hot ocean air like a lid or cap. heat burst A rare phenomenon involving a sudden, localized increase in surface temperature (sometimes 10 °C (18 °F) or more within just a few minutes) associated with a decaying thunderstorm or other mesoscale convective system and possibly accompanied by gusty winds and a rapid decrease in humidity. heat index (HI) Also apparent temperature, felt air temperature, and humiture. A meteorological index that posits the apparent temperature perceived by the average human being who is exposed to a given combination of air temperature and relative humidity in a shaded area. For example, when the air temperature is 32 °C (90 °F) with 70% relative humidity, the heat index is 41 °C (106 °F). heat


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-11.md
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title: Glossary of meteorology
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ice spike A rare ice formation that consists of a long, slender projection of ice extending upward from the surface of a frozen body of water, often in the shape of an inverted icicle. ice storm A type of winter storm characterized by freezing rain which results in the accumulation of at least 6.4 millimetres (0.25 in) of ice on exposed surfaces. icicle A long, slender spike of ice formed when water dripping or falling from an object freezes. incus Indian summer inflow The influx of heat and moisture into a storm system from the surrounding environment. The inflow of parcels of warm, moist air drives and sustains most types of storms, including thunderstorms and tropical cyclones. Contrast outflow. instrument flight rules (IFR) International Standard Atmosphere (ISA) A static atmospheric model of the variations in temperature, pressure, density, and viscosity over a wide range of altitudes within the Earth's atmosphere, established as an international standard by the International Organization for Standardization in order to provide a common reference for atmospheric variables relevant to meteorology and atmospheric science. Intertropical Convergence Zone (ITCZ) Also the doldrums or the calms. irisation See cloud iridescence. == J == jet-effect wind See canyon wind. jet


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-12.md
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title: Glossary of meteorology
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latent heat flux The movement of water vapor (a major transporter of latent heat) from one location to another, e.g. from the tropics toward the poles, where there is a persistent energy deficit relative to lower latitudes. Poleward latent heat flux reaches its global maximum of 1.5 × 1015 watts at latitudes 38 °N and 40 °S. law of storms A general statement of the manner in which the winds of a cyclone rotate about the cyclone's center, and the way in which the entire disturbance moves across the Earth's surface. The development by meteorologists of a "law" describing the general behavior of storms proved important in historical times to sailors navigating during storms at sea. layer cloud See stratiform. lee trough Also lee depression, orographic depression, and dynamic trough. A trough of low atmospheric pressure that forms preferentially to the lee or downwind side of a mountain barrier when air currents flow in directions perpendicular to the barrier and become vertically "squashed" as they cross it. As the column resumes its original depth on the other side of the barrier, it tends to develop a strong spin about its vertical axis, which manifests as a low-pressure center. lee wave


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-13.md
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title: Glossary of meteorology
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MAFOR A North American system used in the transmission of marine weather forecasts to compress large amounts of information about meteorological and marine conditions, including visibility, expected future wind speed and direction, the "state of sea", and the period of validity of the forecast, into shorter code for convenience during radio broadcasting. MAFOR is an abbreviation of MArine FORecast. manometer A scientific instrument consisting of a liquid column gauge used to measure differences in the pressures of gases, as with a mercury barometer. marine climate Also maritime climate. A regional climate that is strongly influenced by its location in relation to a sea or ocean, characterized by relatively small diurnal and seasonal temperature variations and high atmospheric moisture content, which contributes to high precipitation and humidity. Contrast continental climate. marine cloud brightening marine stratocumulus mass flow The movement of a fluid, such as an air mass, down a pressure or temperature gradient. meridional circulation The component of the large-scale atmospheric general circulation that is oriented parallel to a meridian or line of longitude, and thus shows large north–south movement. mesocyclone mesohigh mesolow mesonet mesoscale convective complex (MCC) mesoscale convective discussion (MCD) mesoscale convective system (MCS) mesoscale convective vortex (MCV) mesoscale


id: glossary-of-meteorology-20260505-14
file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-14.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
date_saved: 2026-05-05T07:51:09.813841+00:00
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parent: glossary-of-meteorology-20260505-0
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nephoscope A scientific instrument used to measure the altitude, direction, and velocity of atmospheric clouds relative to a point on the ground directly below them. NEXRAD nimbostratus (Ns) A genus of cloud occurring at low or middle altitudes, typically between 0.5 and 5.5 kilometres (1,600 and 18,000 ft), and often appearing as a dull, dark gray, ragged, nearly uniform sheet or layer that obscures the Sun and produces more or less continuously falling light to moderate precipitation but no lightning or thunder. Low, ragged fractus clouds frequently occur below nimbostratus and may or may not merge with it. noctilucent cloud nonadiabatic process See diabatic process. nor'easter Also northeaster. A macro-scale extratropical cyclone, especially one which impacts the middle and north Atlantic coasts of North America. The name derives from the direction of the winds that most strongly affect the eastern seaboard between the months of October and March. Such storms are often accompanied by very heavy rain or snow, which can cause severe coastal flooding, and hurricane-force winds. Nor'west arch Also Canterbury arch; associated with nor'wester. A conspicuous high-altitude arch-shaped cloud formation that appears regularly in otherwise clear blue skies above the east coast of New Zealand's South Island, when


id: glossary-of-meteorology-20260505-15
file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-15.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
date_saved: 2026-05-05T07:51:09.813841+00:00
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pancake ice A form of ice that consists of round, flat pieces of ice with elevated rims, with diameters ranging from 30 cm (12 in) to 3 m (9.8 ft), and thicknesses of up to 10 cm (3.9 in). pannus Also scud; often used interchangeably with fractus. parhelion Also sun dog or mock sun. An optical phenomenon in which a patch of bright light is visible along the main 22° halo around the Sun, commonly occurring as a pair of such patches with one on either side of the solar disk; the halo itself is not always visible. More rarely, parhelia may occur at other points on the parhelic circle. They are caused by the refraction of sunlight by airborne ice crystals with diameters less than 30 μm (0.0012 in), e.g. those present in cirrus or cirrostratus clouds. Particularly Dangerous Situation pascal (Pa) The SI derived unit of pressure, defined as one newton per square metre. In meteorology, measurements of atmospheric pressure are often given in hectopascals (hPa) or kilopascals (kPa). Pascal's law Also Pascal's principle. A hydrostatic principle which states that pressure applied to a confined incompressible fluid (e.g. air) is transmitted equally and undiminished to every portion of


id: glossary-of-meteorology-20260505-16
file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-16.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
date_saved: 2026-05-05T07:51:09.813841+00:00
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parent: glossary-of-meteorology-20260505-0
summary:
precipitation Any product of the condensation of atmospheric water vapor that falls by gravity, the main forms of which include rain, sleet, snow, hail, and graupel. Precipitation occurs when a portion of the atmosphere becomes locally saturated with water vapor such that the water condenses into liquid or solid droplets and thus "precipitates" out of the atmosphere. pressure gradient The horizontal or vertical rate of change of barometric pressure in the atmosphere, usually expressed in hectopascals (hPa) per metre; the term is also sometimes used more loosely to denote simply the magnitude of the gradient within a pressure field. The three-dimensional pressure gradient vector is usually resolved into its vertical and horizontal components. pressure gradient force (PGF) The force experienced by a unit mass of air in response to differences in atmospheric pressure in either the horizontal or vertical plane, i.e. a pressure gradient, such that air parcels are accelerated away from regions of high pressure and toward regions of low pressure. A strong pressure gradient force leads to intense atmospheric flows and strong winds. pressure system A relative peak or lull in the spatial distribution of sea-level atmospheric pressure. High- and low-pressure systems evolve by the interactions of temperature,


id: glossary-of-meteorology-20260505-17
file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-17.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
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radiation fog Fog formed over land, generally at night in moist, calm air under clear skies. The most common type of fog, it is caused by the radiative cooling of the Earth's surface and the lowest layers of the atmosphere when the temperature of the air near the ground decreases below its dew point. Radiation fog occurs most often in the autumn and winter, and is often deepest around sunrise but usually disperses after dawn when heated by solar radiation. radiatus (ra) A cloud variety characterized by broad parallel bands of cloud that appear to converge because of perspective. This variety may apply to cumulus, stratocumulus, altocumulus, altostratus, or cirrus clouds. radiosonde Also radio-sounding device. A battery-powered scientific instrument released into the atmosphere, usually by a weather balloon, which measures various atmospheric variables and transmits them by radio telemetry to a ground receiver. Radiosondes are essential sources of meteorological data. radius of maximum wind (RMW) The distance between the center of a cyclone and its band of strongest winds, often used as a metric for determining a cyclone's potential intensity. rain A type of precipitation that occurs when liquid water in the form of droplets condenses from atmospheric water vapor,


id: glossary-of-meteorology-20260505-18
file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-18.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
date_saved: 2026-05-05T07:51:09.813841+00:00
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parent: glossary-of-meteorology-20260505-0
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rocketsonde A type of radiosonde that is transported into the upper atmosphere, e.g. the thermosphere, by rocket propulsion before being ejected and descending to the Earth's surface by parachute. Rocketsondes are used to make soundings at altitudes much higher than can usually be obtained by balloon or aircraft. They can provide instantaneous vertical profiles for a number of meteorological variables (temperature, pressure, ozone concentration, wind speed and direction, etc.) as they descend through the layers of the atmosphere. rogue wave roll cloud An elongated, low-level accessory cloud in the shape of a horizontal tube that appears to rotate slowly about its horizontal axis, and is associated with but completely detached from the base of a cumulonimbus cloud above it. Though rare, roll clouds typically occur behind the gust front along the leading edge of a thunderstorm or squall line; they are also sometimes associated with cold fronts. Rossby number Rossby wave Also long wave or planetary wave. A very large-scale atmospheric wave appearing on an upper-air isobaric analysis of the middle and upper troposphere. Rossby waves consist of a series of ridges and troughs with very long wavelengths (typically a few thousand kilometres) stretching around the Earth, principally in the


id: glossary-of-meteorology-20260505-19
file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-19.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
date_saved: 2026-05-05T07:51:09.813841+00:00
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seiche A stationary or standing wave (i.e. a wave that oscillates in time without moving through space) that occurs in an enclosed or semi-enclosed body of water, such as a lake or bay, or in the atmosphere, continuing to oscillate for some time after the force initiating its formation has ceased (occasionally as long as several days). Seiches may be caused by a variety of forces, including strong winds, earthquakes, landslides, and sudden changes in atmospheric pressure. sensible heat The heat absorbed or transmitted by a substance during a change in temperature that is not accompanied by a change of phase (i.e. enthalpy) and which can be measured or "sensed", e.g. with a thermometer. Contrast latent heat. sensible temperature The temperature of the air or an object as it is felt or experienced by an individual. This may differ from the actual measured temperature for any of a number of reasons, e.g. as a result of humidity (as with a heat index) or wind speed (as with wind chill). Compare apparent temperature. severe thunderstorm A type of severe weather consisting of an especially strong or intense thunderstorm accompanied by locally damaging downdraft winds exceeding 50 knots (58 mph), heavy rain,


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-20.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
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sounding rocket Also rocketsonde, research rocket, and suborbital rocket. A sub-orbital rocket carrying scientific instruments designed to record measurements and perform experiments in the upper atmosphere while in flight, usually reaching altitudes ranging from 48 to 145 kilometres (30 to 90 mi) above the surface of the Earth, i.e. higher than weather balloons but lower than weather satellites. specific humidity spindrift Also spoondrift. Sea spray blown from cresting waves during a gale. This spray "drifts" in the direction of the gale and is distinct enough that it is sometimes used to judge wind speed at sea. spring sprite squall A sudden, sharp increase in sustained wind speed that lasts for several minutes, as opposed to a gust, which lasts only for a few seconds. Squalls are technically defined as an increase of at least 8 meters per second (16 kn) to a minimum sustained wind speed of 11 meters per second (21 kn) lasting in excess of one minute, or an increase of at least 3 in force on the Beaufort scale to force 6 or higher. There may be even higher gusts during a squall. They are generally associated with active weather such as rain showers, thunderstorms, or snowstorms,


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-21.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
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terminal aerodrome forecast (TAF) A format for reporting current and forecast weather conditions, particularly as such information relates to aviation. Standard TAFs are issued by major civil airfields at least four times a day (every six hours) and generally apply to a 24- or 30-hour period and an area within approximately 8 kilometres (5.0 mi) from the center of an airport runway complex. TAFs complement and use similar encoding to METAR reports, but also take into account local geographic influences on weather. Terminal Doppler Weather Radar (TDWR) thermal Also thermal column. A column of rising air in the lower altitudes of the Earth's atmosphere. It is a form of atmospheric updraft created by the uneven heating of the Earth's surface by solar radiation, and an example of atmospheric convection. thermal wind The vector difference between the geostrophic wind at two different altitudes in the atmosphere, i.e. the hypothetical vertical wind shear that would exist if the wind obeyed geostrophic balance in the horizontal direction while atmospheric pressure obeyed hydrostatic balance in the vertical direction. The name is derived from the notion of a theoretical wind that blows parallel to the thickness contours plotted on a thickness chart, where the thickness


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-22.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
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troposphere The lowest layer of the Earth's atmosphere, within which nearly all weather phenomena occur. The troposphere contains approximately 75% of the atmosphere's total mass and 99% of its water vapor and aerosols. The average height of the troposphere above the Earth's surface varies between 6 and 18 km (3.7 and 11.2 mi) depending on latitude. trough An elongated region of relatively low atmospheric pressure, often associated with a front. Troughs may exist at the surface or aloft or both; the lifting of moist air by convergent winds usually causes clouds and precipitation to follow immediately behind a trough. Under certain conditions, troughs may alternate with ridges in a high-amplitude pattern. trowal tsunami turbulence Fluid motion characterized by chaotic changes in pressure and flow velocity, caused by excessive kinetic energy in parts of the fluid flow. twilight 1. The indirect illumination of the lower atmosphere caused by the scattering of sunlight when the Sun itself is not directly visible because it is below the horizon. 2. The time period during which such illumination occurs, either between astronomical dawn and sunrise or between sunset and astronomical dusk. TWISTEX An acronym for Tactical Weather-Instrumented Sampling in/near Tornadoes EXperiment. typhoon The local name


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-23.md
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title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
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weather The state of the atmosphere at a given time and location. Weather is driven by a diverse set of naturally occurring phenomena, especially air pressure, temperature, and moisture differences between one place and another, most of which occur in the troposphere. weather balloon Also sounding balloon. A high-altitude balloon used to carry scientific instruments into the atmosphere, which then measure, record, and transmit information about meteorological variables such as atmospheric pressure, temperature, humidity, and wind speed by means of a radiosonde or other measurement device, often one which is expendable. Weather balloons are only feasible in the lower atmosphere and typically do not exceed 40 kilometres (25 mi) in altitude; higher parts of the atmosphere are generally studied with sounding rockets or satellites. weather bomb See explosive cyclogenesis. weather forecasting The application of science and technology to predict the conditions of the atmosphere at a given time and location. Weather forecasts are made by collecting quantitative data about the current state of the atmosphere at a given place and then using meteorology to project how the atmosphere will change. Forecasting is important to a wide variety of human activities, including business, agriculture, transportation, recreation and general health and safety,


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file: data/en.wikipedia.org/wiki/Glossary_of_meteorology-24.md
category: reference
title: Glossary of meteorology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_meteorology
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windsock A tapered conical tube made from a lightweight fabric, often brightly colored and hung loosely from a pole in an open area in order to serve as a simple visual indicator of wind speed and direction by filling with air as the wind blows. A windsock fills and points in the opposite direction from which the wind is blowing (e.g. if the wind is blowing from the west, the windsock will point east), and the angle at which it hangs from the pole can provide a basic approximation of wind speed (e.g. if the wind is very light, the windsock may hang limply at a shallow angle; if it is very strong, the windsock may point straight out from the pole and flap wildly). Windsocks are commonly employed at airports to provide useful real-time visual approximations of the wind's strength and direction to pilots. winter winter storm Often used interchangeably with snowstorm. 1. Any storm which occurs during the local winter. 2. Any meteorological event in which varieties of precipitation which can only occur at low temperatures are formed, such as snow, sleet, or freezing rain. Such events are not necessarily restricted to the winter season but may occur


id: glossary-of-physics-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_physics-0.md
category: reference
title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
date_saved: 2026-05-05T07:51:11.278375+00:00
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This glossary of physics is a list of definitions of terms and concepts relevant to physics, its sub-disciplines, and related fields, including mechanics, materials science, nuclear physics, particle physics, and thermodynamics. For more inclusive glossaries concerning related fields of science and technology, see Glossary of chemistry terms, Glossary of astronomy, Glossary of areas of mathematics, and Glossary of engineering. == A == ab initio A mathematical model which seeks to describe atomic nuclei by solving the non-relativistic Schrödinger equation for all constituent nucleons and the forces that exist between them. Such methods yield precise results for very light nuclei but become more approximate for heavier nuclei. Abbe number Also called the V-number or constringence. In optics and lens design, a measure of a transparent material's dispersion (a variation of refractive index versus wavelength). High values of V indicate low dispersion. absolute electrode potential In electrochemistry, the electrode potential of a metal measured with respect to a universal reference system (without any additional metal–solution interface). absolute humidity The ratio of the water vapor in a sample of air to the volume of the sample. absolute motion absolute pressure Is zero-referenced against a perfect vacuum, using an absolute scale, so it is


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file: data/en.wikipedia.org/wiki/Glossary_of_physics-1.md
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title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
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alternating current (AC) A form of electric current in which the movement of electric charge periodically reverses direction. Contrast direct current. ammeter An instrument used to measure electric current. amorphous solid A type of solid which does not have a definite geometric shape. ampere (A) Often abbreviated as amp. The SI base unit of electric current, defined as one coulomb of electric charge per second. amplifier Also electronic amplifier or (informally) amp. An electronic device that can increase the power of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude of a signal applied to its input terminals, producing a proportionally greater amplitude signal at its output. The amount of amplification provided by an amplifier is measured by its gain: the ratio of output voltage, current, or power to input. By definition, an amplifier is any circuit that has a power gain greater than one. amplitude The height of a wave as measured from its center (normal) position. angle of incidence In geometric optics, the angle between a ray incident on a surface and the line perpendicular to the surface at the point of


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file: data/en.wikipedia.org/wiki/Glossary_of_physics-2.md
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title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
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anode The electrode through which a conventional electric current flows into a polarized electrical device; the direction of current flow is, by convention, opposite to the direction of electron flow, and so electrons flow out of the anode. In a galvanic cell, the anode is the negative terminal or pole which emits electrons toward the external part of an electrical circuit. However, in an electrolytic cell, the anode is the wire or plate having excess positive charge, so named because negatively charged anions tend to move towards it. Contrast cathode. anti-gravity A theory of creating a place or object that is free from the force of gravity. It does not refer to the lack of weight under gravity experienced in free fall or orbit, or to balancing the force of gravity with some other force, such as electromagnetism or aerodynamic lift. antimatter antineutron The antiparticle of the neutron, with symbol n. It differs from the neutron only in that some of its properties have equal magnitude but opposite sign. It has the same mass as the neutron, and no net electric charge, but has opposite baryon number (+1 for the neutron, −1 for the antineutron). This is because the antineutron


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file: data/en.wikipedia.org/wiki/Glossary_of_physics-3.md
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title: Glossary of physics
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source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
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baryon A class of composite subatomic particle in the hadron family, such as a proton or a neutron, each of which is made of (usually) three quarks. Nearly all matter humans are likely to encounter is baryonic matter. Baryons are also considered fermions. battery A combination of two or more electrical cells which produces electricity. beam A structural element that is capable of withstanding a load primarily by resisting bending. Beams are traditionally descriptions of building or civil engineering structural elements, but smaller structures such as truck or automobile frames, machine frames, and other mechanical or structural systems contain beam structures that are designed and analyzed in a similar fashion. bending Also known as flexure. The behavior of a slender structural element (e.g. a beam) which is subjected to an external load applied perpendicularly to a longitudinal axis of the element. bending moment The reaction induced in a structural element when an external force or moment is applied to the element, causing the element to bend. The simplest structural element subjected to bending moments is the beam. Bernoulli equation Bernoulli's principle In fluid dynamics, a principle which states that an increase in the speed of a fluid occurs simultaneously with


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file: data/en.wikipedia.org/wiki/Glossary_of_physics-4.md
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title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
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Brownian motion Also pedesis. The apparently random movement of particles suspended in a fluid (liquid or gas) resulting from their continuous bombardment by fast-moving atoms or molecules in the gas or liquid. bubble A globule of a gaseous substance immersed or suspended in a liquid; e.g. a pocket of air completely enclosed by water, usually but not necessarily assuming a spherical shape. Bulk modulus A measure of a substance's resistance to uniform compression defined as the ratio of the infinitesimal pressure increase to the resulting relative decrease of the volume. Its base unit is the pascal. buoyancy An upward force exerted by a fluid that opposes the weight of an immersed object. == C == calculus A branch of mathematics that studies change and has two major sub-fields: differential calculus (concerning rates of change and slopes of curves), and integral calculus (concerning accumulation of quantities and the areas under and between curves). These two branches are related to each other by the fundamental theorem of calculus. capacitance The ratio of the change in the electric charge of a system to the corresponding change in its electric potential. There are two closely related notions of capacitance: self capacitance and mutual capacitance.


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file: data/en.wikipedia.org/wiki/Glossary_of_physics-5.md
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title: Glossary of physics
tags: science, encyclopedia
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classical mechanics Also Newtonian mechanics. A sub-field of mechanics concerned with the set of physical laws describing the motion of bodies under the collective actions of a system of forces. coefficient of friction coherence cohesion The tendency of similar particles or surfaces to cling to one another. Contrast adhesion. cold fusion complex harmonic motion composite particle Compton scattering A type of light–matter interaction in which a photon is scattered by a charged particle, usually an electron, which results in part of the energy of the photon being transferred to the recoiling electron; a resulting decrease in the energy of the photon is called the Compton effect. The opposite phenomenon occurs in inverse Compton scattering, when a charged particle transfers part of its energy to a photon. concave lens condensation point condensed matter physics A branch of physics that studies the physical properties of condensed phases of matter. conservation of momentum conservation law constructive interference continuous spectrum continuum mechanics convection The transfer of heat by the actual transfer of matter. convex lens coulomb (C) The SI derived unit of electric charge, defined as the charge transported by a constant current of one ampere in one second. Coulomb's law converging lens cosmic


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title: Glossary of physics
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source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
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electrical insulator Also simply insulator. Any material whose internal electric charges do not flow freely and which therefore does not readily conduct an electric current under the influence of an electric field. electrical potential energy electrical and electronics engineering electrical network An interconnection of electrical elements such as resistors, inductors, capacitors, voltage sources, current sources, and switches. electrical resistance Also simply resistance. The opposition to the passage of an electric current through an electrical element. Good insulators typically have very high electrical resistance. electricity The set of physical phenomena associated with the presence and flow of electric charges. electro-optic effect electrochemical cell electrodynamics electrolytic cell electromagnet A type of magnet in which the magnetic field is produced by the flow of an electric current. electromagnetic field Also abbreviated EM field or EMF. A physical field produced by moving electrically charged objects. electromagnetic induction electromagnetic radiation Also abbreviated EM radiation or EMR. A form of energy emitted and absorbed by charged particles, which exhibits wave-like behavior as it travels through space. electromagnetic spectrum electromagnetic wave equation electromagnetism electromechanics electromotive force ( E {\displaystyle {\mathcal {E}}} ) Also abbreviated emf. The electrical intensity or "pressure" developed by a source of electrical energy


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file: data/en.wikipedia.org/wiki/Glossary_of_physics-7.md
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title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
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graviton A hypothetical elementary particle that meditates the force of gravitation. gravity See gravitation. ground ground reaction force ground state group velocity == H == hadron A composite particle made from two or more quarks held together by the strong force. Protons and neutrons are both considered hadrons. half-life The time required for a quantity to fall to half its value as measured at the beginning of the time period. In physics, half-life typically refers to a property of radioactive decay, but may refer to any quantity which follows an exponential decay. Hamilton's principle Hamiltonian mechanics harmonic mean heat A form of energy transferred from one body to another by thermal interaction. heat transfer Helmholtz free energy hertz The SI unit of frequency, defined as the number of cycles per second of a periodic phenomenon. Higgs boson homeokinetics The physics of complex, self-organizing systems. horsepower (hp) Huygens–Fresnel principle hydrostatics == I == ice point A physical process that results in the phase transition of a substance from a liquid to a solid. impedance The measure of the opposition that an electric circuit presents to a current when a voltage is applied. implosion impulse The change in momentum, which is equal


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file: data/en.wikipedia.org/wiki/Glossary_of_physics-8.md
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title: Glossary of physics
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parent: glossary-of-physics-20260505-0
summary:
liquid crystal (LC) A state of matter which has properties between those of a conventional liquid and those of a solid crystal. For instance, an LC may flow like a liquid, but its molecules may be oriented in a crystal-like way. longitudinal wave == M == M-theory An extension of string theory that attempts to unify seemingly contradictory mathematical formulations and which identifies 11 dimensions. Mach number A dimensionless quantity representing the ratio of the speed of an object moving through a fluid to the local speed of sound. Mach's principle The proposition that the existence of absolute rotation (the distinction of local inertial frames vs. rotating reference frames) is determined by the large-scale distribution of matter. machine Any powered tool consisting of one or more parts that is constructed to achieve a particular goal. Machines are usually powered by mechanical, chemical, thermal, or electrical means, and are frequently motorised. machine element An elementary component of a machine. There are three basic types: structural components, mechanisms, and control components. Maclaurin series A representation of a function as an infinite sum of terms that are calculated from the values of the function's derivatives at a single point. magnetic field A mathematical


id: glossary-of-physics-20260505-9
file: data/en.wikipedia.org/wiki/Glossary_of_physics-9.md
category: reference
title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
date_saved: 2026-05-05T07:51:11.278375+00:00
instance: kb-cron
parent: glossary-of-physics-20260505-0
summary:
nanotechnology Also abbreviated as nanotech. The manipulation of matter on an atomic and molecular scale; a more generalized description by the National Nanotechnology Initiative is "the manipulation of matter with at least one dimension sized from 1 to 100 nanometres". Navier–Stokes equations neurophysics neutrino A type of electrically neutral subatomic particle denoted by the Greek letter ν (nu). All evidence suggests that neutrinos have mass but that their mass is tiny even by the standards of subatomic particles. Their mass has never been measured accurately. neutron A subatomic particle having a mass slightly greater than that of a proton but no electric charge. Along with protons they constitute the nucleus of every atom. Each neutron consists of one up quark and two down quarks. prompt neutron Immediate emission of neutrons after a nuclear fission event. delayed neutron Delayed emission of neutrons after a nuclear fission event, by one of the fission products (actually, a fission product daughter after beta decay). neutron cross-section newton (N) Newton's laws of motion A set of three physical laws which describe the relationship between the forces acting on a body and its motion due to those forces. Together they form the basis for classical or


id: glossary-of-physics-20260505-10
file: data/en.wikipedia.org/wiki/Glossary_of_physics-10.md
category: reference
title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
date_saved: 2026-05-05T07:51:11.278375+00:00
instance: kb-cron
parent: glossary-of-physics-20260505-0
summary:
quark An elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. quasiparticle == R == radiant energy radiation radioactive decay radionuclide Also radioactive nuclide, radioisotope, or radioactive isotope. Any nuclide possessing excess nuclear energy to the point that it is unstable. Such excess energy is emitted through any of several processes of radioactive decay, resulting in a stable nuclide or sometimes another unstable radionuclide which can then undergo further decay. Certain radionuclides occur naturally; many others can be produced artificially in nuclear reactors, cyclotrons, particle accelerators, or radionuclide generators. radius of curvature redshift A phenomenon which occurs when light seen coming from an object that is moving away from the observer is proportionally increased in wavelength or "shifted" to the red end of the visible light spectrum. refraction The change in direction of a wave as it passes from one transmission medium to another or as a result of a gradual change in the medium. Though most commonly used in the context of refraction of light, other waves such as sound waves and fluid waves also experience refraction. refractive


id: glossary-of-physics-20260505-11
file: data/en.wikipedia.org/wiki/Glossary_of_physics-11.md
category: reference
title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
date_saved: 2026-05-05T07:51:11.278375+00:00
instance: kb-cron
parent: glossary-of-physics-20260505-0
summary:
stiffness The rigidity of an object, i.e. the extent to which it resists deformation in response to an applied force. strain The transformation of a body from a reference configuration to a current configuration. A configuration is a set containing the positions of all particles of the body. strain hardening strength of materials stress 1. An applied force or system of forces that tends to strain or deform a physical body. 2. A measure of the internal forces acting within a deformable body. 3. A quantitative measure of the average force per unit area of a surface within a body on which internal forces act. stress–strain curve string duality string theory strong interaction Also strong force and strong nuclear force. structural load subatomic particle Any particle that is smaller than an atom. sublimation The physical process by which matter is transformed directly from the solid phase to the gas phase without passing through an intermediate liquid phase. Sublimation is an endothermic phase transition that occurs at temperatures and pressures below a substance's triple point in its phase diagram. superconductivity superconductor A phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a


id: glossary-of-physics-20260505-12
file: data/en.wikipedia.org/wiki/Glossary_of_physics-12.md
category: reference
title: Glossary of physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_physics
date_saved: 2026-05-05T07:51:11.278375+00:00
instance: kb-cron
parent: glossary-of-physics-20260505-0
summary:
weak interaction Also weak force or weak nuclear force. One of the four fundamental forces of nature, along with the strong nuclear force, electromagnetism, and gravitation. It is responsible for the radioactive decay of subatomic particles and initiates the process known as hydrogen fusion in stars. weber (Wb) wedge A triangular round tool in the form of a compound and portable inclined plane; one of six classical simple machines. weight wheel and axle A wheel attached to an axle in such a way that the two parts rotate together and transfer forces between them; one of six classical simple machines. white body A hypothetical idealized physical body that reflects all incident electromagnetic radiation completely and uniformly in all directions; the opposite of a black body. wind The flow of gases on a large scale. work work function == X == X-ray A high-energy photon (between 100 eV and 100 keV) with a wavelength shorter than that of ultraviolet radiation and longer than that of gamma radiation. == Y == Young’s modulus A measure of the stiffness of a solid material which defines the relationship between mechanical stress and strain. == Z == Zeeman effect The effect of splitting a spectral


id: glossary-of-power-electronics-20260505-0
file: data/en.wikipedia.org/wiki/Glossary_of_power_electronics-0.md
category: reference
title: Glossary of power electronics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_power_electronics
date_saved: 2026-05-05T07:51:12.696950+00:00
instance: kb-cron
parent: glossary-of-power-electronics-20260505-0
summary:
This glossary of power electronics is a list of definitions of terms and concepts related to power electronics in general and power electronic capacitors in particular. For more definitions in electric engineering, see Glossary of electrical and electronics engineering. For terms related to engineering in general, see Glossary of engineering. The glossary terms fit in the following categories in power electronics: Electronic power converters; converters, rectifiers, inverters, filters. Electronic power switches and electronic AC power converters; switches and controllers. Essential components of electric power equipment; device, stack, assembly, reactor, capacitor, transformer, AC filter, DC filter, snubber circuit. Circuits and circuit elements of power electronic equipment; arms and connections. Operations within power electronic equipment; commutations, quenchings, controls, angles, factors, states, directions, intervals, periods, frequencies, voltages, breakthroughs and failures, breakdowns, blocking and flows. Properties of power electronic equipment Characteristic curves of power electronic equipment Power supplies == A == AC capacitor A capacitor essentially designed for operation with alternating voltage.AC conversion factor For AC conversion, the ratio of the fundamental output power to the fundamental input power. AC converter A converter for AC conversion. AC filter A filter on the AC side of a converter, designed to reduce the circulation of harmonic


id: glossary-of-power-electronics-20260505-1
file: data/en.wikipedia.org/wiki/Glossary_of_power_electronics-1.md
category: reference
title: Glossary of power electronics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_power_electronics
date_saved: 2026-05-05T07:51:12.696950+00:00
instance: kb-cron
parent: glossary-of-power-electronics-20260505-0
summary:
circuit off-state interval The interval during which a controllable valve device or an arm consisting of such devices is in the off state. characteristic (curve) (of a converter) A curve showing the relationship between the values of the output voltage and the values of the output current. commutating voltage The voltage which causes the current to commutate. commutation In a power converter the transfer of current from one conducting arm to the next to conduct in sequence, without interruption of the current, both arms conducting simultaneously during a finite time interval. commutation circuit The circuit consisting of the commutating arms and the source providing the commutating voltage. commutating group A group of principal arms which commutate cyclically among themselves without intermediate commutation of the current to other principal arms. commutation capacitor A capacitor included in the commutation circuit to supply commutating voltage. commutation inductance The resulting inductance in the commutation circuit. commutation interval The time interval in which commutating arms are carrying principal current simultaneously. commutation failure A failure to commutate the current from a conducting arm to the succeeding arm. commutation notch A periodic voltage transient that may appear in the AC side voltage of a line or machine


id: glossary-of-power-electronics-20260505-2
file: data/en.wikipedia.org/wiki/Glossary_of_power_electronics-2.md
category: reference
title: Glossary of power electronics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_power_electronics
date_saved: 2026-05-05T07:51:12.696950+00:00
instance: kb-cron
parent: glossary-of-power-electronics-20260505-0
summary:
DC conversion factor for DC conversion, the ratio of the DC power value on the load side to that on the source side. (electronic) DC (power) conversion Electronic conversion from DC to DC DC filter A filter on the DC side of a converter, designed to reduce the ripple in the associated system. DC form factor The ratio of the rms value to the mean value averaged over a full period of a periodically varying quantity having a non zero DC component. DC power The product of the direct voltage and the direct current (mean values). DC ripple factor The ratio of half the difference between the maximum and minimum value of a pulsating direct current to the mean, value of this current. direct AC/DC converter An electronic AC/DC converter without a DC or AC link. direct AC converter An AC converter without a DC link. direct (power) conversion Electronic conversion without a DC or AC link. direct DC converter DC chopper A DC converter without an AC link. direct commutation A commutation between two principal arms without transfer through any auxiliary arms. direct inverter An inverter without a DC link. direct rectifier A rectifier without a DC or AC


id: glossary-of-power-electronics-20260505-3
file: data/en.wikipedia.org/wiki/Glossary_of_power_electronics-3.md
category: reference
title: Glossary of power electronics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_power_electronics
date_saved: 2026-05-05T07:51:12.696950+00:00
instance: kb-cron
parent: glossary-of-power-electronics-20260505-0
summary:
indirect (power) conversion Electronic conversion with one or more DC or AC link(s). indirect current link AC converter An AC converter with a current stiff DC link . indirect DC converter A DC converter with an AC link. indirect inverter An inverter with a DC link. indirect rectifier A rectifier with a DC or AC link. indirect voltage link AC converter An AC converter with a voltage stiff DC link. inductive direct voltage regulation The direct voltage regulation due to the commutation inductance(s). influence quantity In the field of power electronics any quantity generally external to a power supply which may affect its performance. inherent delay angle The current delay angle occurring, even without phase control, caused by multiple overlap. inherent direct voltage regulation The direct voltage regulation excluding the effect of the AC system impedance. intermittent flow (of direct current) A flow of direct current which is periodically interrupted. internal discharge device A device incorporated in the capacitor connecting the terminals of the unit, capable of reducing the residual voltage effectively to zero after the capacitor has been disconnected from the supply. internal (element) fuse A device incorporated in the capacitor which disconnects an element or a group of


id: glossary-of-power-electronics-20260505-4
file: data/en.wikipedia.org/wiki/Glossary_of_power_electronics-4.md
category: reference
title: Glossary of power electronics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_power_electronics
date_saved: 2026-05-05T07:51:12.696950+00:00
instance: kb-cron
parent: glossary-of-power-electronics-20260505-0
summary:
operating temperature (capacitor) The temperature of the hottest point on the case of the capacitor in thermal equilibrium. overpressure disconnector A disconnecting device designed to interrupt the current path in the case of abnormal increase of the internal pressure. == P == pair of antiparallel arms Two valve arms in parallel with opposite conducting directions. pair of arms Two series connected valve arms with the same conducting direction. parallel operation A mode of operation of stabilized power supplies in which all similar output terminals are connected together and arranged so that the total load is shared by all the supplies. phase control factor In the case of phase control, the ratio of the voltage at prevailing current delay angle to the voltage at zero current delay angle, all voltage drops being assumed to be zero. phase converter An AC converter for changing the number of phases. phase control The process of varying the instant within the cycle at which current conduction in an electronic valve device or a valve arm begins. power electronic capacitor A power capacitor intended to be used in power electronic equipment and capable of operating continuously under non-sinusoidal current or voltage. power electronics The field of


id: glossary-of-power-electronics-20260505-5
file: data/en.wikipedia.org/wiki/Glossary_of_power_electronics-5.md
category: reference
title: Glossary of power electronics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossary_of_power_electronics
date_saved: 2026-05-05T07:51:12.696950+00:00
instance: kb-cron
parent: glossary-of-power-electronics-20260505-0
summary:
stabilized power supply In the field of power electronics an equipment which takes electrical energy from a source and supplies it stabilized by means inside the equipment to one or more pairs of output terminals. stage (of a series connection) A part of a series connection of two or more converter connections consisting of one or more parallel connected converter connections. steady-state condition (capacitor) Thermal equilibrium attained by the capacitor at constant output and at constant cooling-air temperature. symmetrical phase control Phase control with equal delay angles in all principal arms of a fully controllable converter connection or commutating group. switched valve device A controllable valve device which may be turned on and off by a control signal. == T == tangent of the loss angle (tanδ) of a capacitor The ratio between the equivalent series resistance and the capacitive reactance of a capacitor at specified sinusoidal alternating voltage and frequency. threshold voltage (of an electronic valve device) The value of the voltage obtained at the intersection of the voltage axis and the straight line approximation of the on-state characteristic of an electronic valve device. transfer factor (of a DC converter) The ratio of the voltage on the load side


id: list-of-topics-characterized-as-pseudoscience-20260505-0
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-0.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
This is a list of topics that have, either currently or in the past, been characterized as pseudoscience by academics or researchers. Detailed discussion of these topics may be found on their main pages. Criticism of pseudoscience, generally by the scientific community or skeptical organizations, involves critiques of the logical, methodological, or rhetorical bases of the topic in question. Though some of the listed topics continue to be investigated scientifically like psychoanalysis, others were only subject to scientific research in the past and today are considered refuted, but resurrected in a pseudoscientific fashion. Other ideas presented here are entirely non-scientific, but have in one way or another impinged on scientific domains or practices. Many adherents or practitioners of the topics listed here dispute their characterization as pseudoscience. Each section here summarizes the alleged pseudoscientific aspects of that topic. == Physical sciences == === Astronomy and space sciences === 2012 phenomenon – a range of eschatological beliefs that cataclysmic or otherwise transformative events would occur on or around 21 December 2012. This date was regarded as the end-date of a 5,126-year-long cycle in the Mesoamerican Long Count calendar and as such, festivities to commemorate the date took place on 21 December


id: list-of-topics-characterized-as-pseudoscience-20260505-1
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-1.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
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parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
=== Earth sciences === Megalithic geometry or 366 geometry – posits the existence of an Earth-based geometry dating back to at least 3500 BCE and the possibility that such a system is still in use in modern Freemasonry. According to proponents, megalithic civilizations in Britain and Brittany had advanced knowledge of geometry and the size of Earth. The megalithic yard is correlated to the polar circumference of Earth using a circle divided into 366 degrees. The Bermuda Triangle – a region of the Atlantic Ocean that lies between Bermuda, Puerto Rico and (in its most popular version) Florida. Ship and aircraft disasters and disappearances perceived as frequent in this area have led to the circulation of stories of unusual natural phenomena, paranormal encounters and interactions with extraterrestrials. Climate change denial – involves denial, dismissal, unwarranted doubt or contrarian views which depart from the scientific consensus on climate change, including the extent to which it is caused by humans, its impacts on nature and human society, or the potential of adaptation to global warming by human actions. Flood geology – creationist form of geology that advocates most of the geologic features on Earth are explainable by a global flood. The Hollow


id: list-of-topics-characterized-as-pseudoscience-20260505-2
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-2.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
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parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
=== Agriculture === Lysenkoism, or Lysenko-Michurinism – was a political campaign against genetics and science-based agriculture conducted by Trofim Lysenko, his followers and Soviet authorities. Lysenko served as the director of the Soviet Union's Lenin All-Union Academy of Agricultural Sciences. Lysenkoism began in the late 1920s and formally ended in 1964. The pseudoscientific ideas of Lysenkoism built on Jean-Baptiste Lamarck's concepts of the heritability of acquired characteristics. Lysenko's theory rejected Gregor Mendel's theory of inheritance and the concept of the "gene"; it departed from Darwinian evolutionary theory by rejecting natural selection, viewing that concept as being incompatible with Marxist ideology. Biodynamic agriculture – method of organic farming that treats farms as unified and individual organisms. Biodynamics uses a calendar which has been characterized as astrological. The substances and composts used by biodynamicists have been described as unconventional and homeopathic. For example, field mice are countered by deploying ashes prepared from field mice skin when Venus is in the Scorpius constellation. No difference in beneficial outcomes has been scientifically established between certified biodynamic agricultural techniques and similar organic and integrated farming practices. Biodynamic agriculture lacks strong scientific evidence for its efficacy and has been labeled a pseudoscience because of its overreliance


id: list-of-topics-characterized-as-pseudoscience-20260505-3
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-3.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
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parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
The abortion–breast cancer hypothesis posits that having an induced abortion can increase the risk of breast cancer. This hypothesis is at odds with mainstream scientific opinion and is rejected by major medical professional organizations. Access Consciousness is an alternative medicine technique similar to a combination of phrenology, reiki, energy therapies and therapeutic touch, where health and wellness can be improved by touching the 32 "Energy Bars" on a person's head. Acupuncture – use of fine needles to stimulate acupuncture points and balance the flow of qi. There is no known anatomical or histological basis for the existence of acupuncture points or meridians and acupuncture is regarded as an alternative medical procedure. Some acupuncturists regard them as functional rather than structural entities, useful in guiding evaluation and care of patients. Acupuncture has been the subject of active scientific research since the late 20th century and its effects and application remain controversial among medical researchers and clinicians. Some scholarly reviews conclude that acupuncture's effects are mainly attributable to the placebo effect and others find likelihood of efficacy for particular conditions. Dry needling is the therapeutic insertion of fine needles without regard to traditional Chinese medicine (TCM) and is similarly controversial. Acupressure is


id: list-of-topics-characterized-as-pseudoscience-20260505-4
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-4.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
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parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
There is disputed evidence that it may be effective in combating postoperative nausea and vomiting. Auriculotherapy (also auricular therapy, ear acupuncture, and auriculoacupuncture) is a form of alternative medicine based on the idea that the ear is a micro-system which reflects the entire body, represented on the auricle, the outer portion of the ear. Conditions affecting the physical, mental or emotional health of the patient are assumed to be treatable by stimulation of the surface of the ear exclusively. Similar mappings are used in many areas of the body, including the practices of reflexology and iridology. These mappings are not based on or supported by any medical or scientific evidence and are therefore considered to be pseudoscience. Autistic enterocolitis is a nonexistent medical condition proposed by discredited British gastroenterologist Andrew Wakefield when he suggested a link between a number of common clinical symptoms and signs which he contended were distinctive to autism. The existence of such an enterocolitis has been dismissed by experts as having "not been established". Wakefield's now-retracted and fraudulent report used inadequate controls and suppressed negative findings and multiple attempts to replicate his results have been unsuccessful. Reviews in the medical literature have found no link between


id: list-of-topics-characterized-as-pseudoscience-20260505-5
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-5.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
Chromotherapy, sometimes called color therapy, colorology or cromatherapy, is an alternative medicine method which is considered pseudoscience. Chromotherapists claim to be able to use light in the form of color to balance "energy" lacking from a person's body, whether it be on physical, emotional, spiritual, or mental levels. Color therapy is distinct from other types of light therapy, such as neonatal jaundice treatment and blood irradiation therapy, which is a scientifically accepted medical treatment for a number of conditions, and from photobiology, the scientific study of the effects of light on living organisms. French skeptic and lighting physicist Sébastien Point considers LED lamps at domestic radiance to be safe in normal use for the general population; he also pointed out the risk of overexposure to light from LEDs for practices like chromotherapy, when duration and time exposure are not under control. Chronic Lyme disease (not to be confused with Lyme disease) is a generally rejected diagnosis that encompasses "a broad array of illnesses or symptom complexes for which there is no reproducible or convincing scientific evidence of any relationship to Borrelia burgdorferi infection." Despite numerous studies, there is no clinical evidence that "chronic" Lyme disease is caused by a persistent


id: list-of-topics-characterized-as-pseudoscience-20260505-6
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-6.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
The field has been compared to pseudoscience due to irreproducible or contradictory findings, exaggerated claims of usefulness and lack of high quality research protocols. Ear candling, also called ear coning or thermal-auricular therapy, is a pseudoscientific alternative medicine practice claimed to improve general health and well-being by lighting one end of a hollow candle and placing the other end in the ear canal. Medical research has shown that the practice is both dangerous and ineffective and does not functionally remove earwax or toxicants, despite product design contributing to that impression.


id: list-of-topics-characterized-as-pseudoscience-20260505-7
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-7.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
Earthing therapy or grounding is a therapy that is claimed to ease pain, provide a better night's sleep, and assist with symptoms of inflammation by being in direct physical contact with the ground or a device connected to electrical ground. Practitioners claim that Earth has an excess of electrons which people are missing due to insulating shoes and ground cover. Being in electrical contact with Earth is claimed to provide the body with those excess electrons, which then act as antioxidants. A 2012 systematic review study showed inconclusive results related to methodological issues across the literature. Subsequently, a 2017 systematic review of the benefits of spending time in forests demonstrated positive health effects, but not enough to generate clinical practice guidelines or demonstrate causality. Electrohomeopathy (or Mattei cancer cure) is a derivative of homeopathy invented in the 19th century by Count Cesare Mattei. The name is derived from a combination of electro (referring to an electric bio-energy content supposedly extracted from plants and of therapeutic value, rather than electricity in its conventional sense) and homeopathy (referring to an alternative medicinal philosophy developed by Samuel Hahnemann in the 18th century). Electrohomeopathy has been defined as the combination of electrical devices and


id: list-of-topics-characterized-as-pseudoscience-20260505-8
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-8.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
Systematic reviews of clinical trials of Bach flower solutions have found no efficacy beyond a placebo effect. Iridology – means of medical diagnosis which proponents believe can identify and diagnose health problems through close examination of the markings and patterns of the iris. Practitioners divide the iris into 80–90 zones, each of which is connected to a particular body region or organ. This connection has not been scientifically validated and disorder detection is neither selective nor specific. Because iris texture is a phenotypical feature which develops during gestation and remains unchanged after birth (which makes the iris useful for Biometrics), iridology is all but impossible. Jilly Juice – a potentially dangerous fermented drink that has been claimed to treat a variety of medical conditions. Leaky gut syndrome – in alternative medicine, a proposed condition caused by the passage of harmful substances outward through the gut wall. It has been proposed as the cause of many conditions, including multiple sclerosis and autism, a claim which has been called pseudoscientific. According to the UK National Health Service, the theory is vague and unproven. Some skeptics and scientists say that the marketing of treatments for leaky gut syndrome is either misguided or an


id: list-of-topics-characterized-as-pseudoscience-20260505-9
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-9.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
Radionics – means of medical diagnosis and therapy which proponents believe can diagnose and remedy health problems using various frequencies in a putative energy field coupled to the practitioner's electronic device. The first such "black box" devices were designed and promoted by Albert Abrams and were definitively proven useless by an independent investigation commissioned by Scientific American in 1924. The internal circuitry of radionics devices is often obfuscated and irrelevant, leading proponents to conjecture dowsing and ESP as operating principles. Similar devices continue to be marketed under various names, though none is approved by the U.S. Food and Drug Administration; there is no scientific evidence for the efficacy or underlying premise of radionics devices. The radionics of Albert Abrams and his intellectual descendants should not be confused with similarly named reputable and legitimate companies, products, or medical treatments such as radiotherapy or radiofrequency ablation. Reiki is a form of alternative medicine called energy healing. Reiki practitioners use a technique called palm healing or hands-on healing through which a "universal energy" is said to be transferred through the palms of the practitioner to the patient in order to encourage emotional or physical healing. Reiki is a pseudoscience, and is used as


id: list-of-topics-characterized-as-pseudoscience-20260505-10
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-10.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
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parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
Research concerning qigong has been conducted for a wide range of medical conditions, including hypertension, pain and cancer, and with respect to quality of life. Most research concerning health benefits of qigong has been of poor quality, such that it would be unwise to draw firm conclusions at this stage. Zang-fu – concept of organs as functional yin and yang entities for the storage and manipulation of qi. These organs are not based in anatomy. Tomatis Method A type of auditory integration training devised by Alfred A. Tomatis and promoted, without supporting evidence, as being of benefit to people with autism. Urine therapy – drinking either one's own undiluted urine or homeopathic potions of urine for treatment of a wide variety of diseases is based on pseudoscience. Promotion of a link between autism and vaccines, in which the vaccines are accused of causing autism-spectrum conditions, triggering them, or aggravating them, has been characterized as pseudoscience. Many epidemiological studies have reported no association between either the MMR vaccine and autism, or thimerosal-containing vaccines and autism. Consequently, the Institute of Medicine has concluded that there is no causal link between either of these varieties of vaccines and autism. Similarly, "vaccine overload", a


id: list-of-topics-characterized-as-pseudoscience-20260505-11
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-11.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
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parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
=== Technology === 5G conspiracies and 5G causes coronavirus theories – theory proposing that 5G causes health issues, including COVID-19. == Social sciences == === History === Christ myth theory – A fringe theory that proposes that the historical Jesus did not exist in any capacity whatsoever. While the divinity of Jesus is a matter of religious and philosophical rather than historical debate, Christian and non-Christian scholars of antiquity universally agree that Jesus of Nazareth was a Galilean Jew who lived in the first century, was baptized, and later crucified by Roman authorities. This is based on sources written by historians, scholars, and politicians who lived during the time of Christ. Holocaust denial – Historical revisionist movements associated with Holocaust denial have employed pseudoscientific evidence and conspiracy theories published in intradiegetic pseudo-academic journals and presented at fringe conferences (e.g. misconstruing cyanide residue studies, claiming despite all evidence to the contrary that gas chambers were built after the war). Khazar hypothesis of Ashkenazi ancestry – A fringe theory that postulates that Ashkenazi Jews were primarily, or to a large extent, descended from Khazars, a multi-ethnic conglomerate of mostly Turkic peoples who formed a semi-nomadic khanate in and around the northern and


id: list-of-topics-characterized-as-pseudoscience-20260505-12
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-12.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
=== Psychology === Attachment therapy – common name for a set of potentially fatal clinical interventions and parenting techniques aimed at controlling aggressive, disobedient, or unaffectionate children using "restraint and physical and psychological abuse to seek their desired results." (The term "attachment therapy" may sometimes be used loosely to refer to mainstream approaches based on attachment theory, usually outside the US where the pseudoscientific form of attachment therapy is less known.) Probably the most common form is holding therapy, in which the child is restrained by adults for the purpose of supposed cathartic release of suppressed rage and regression. Perhaps the most extreme, but much less common, is "rebirthing", in which the child is wrapped tightly in a blanket and then made to simulate emergence from a birth canal. This is done by encouraging the child to struggle and pushing and squeezing them to mimic contractions. Despite the practice's name, it is not based on traditional attachment theory and shares no principles of mainstream developmental psychology research. In 2006, it was the subject of an almost entirely critical Taskforce Report commissioned by the American Professional Society on the Abuse of Children (APSAC). Conversion therapy – sometimes called reparative therapy, seeks


id: list-of-topics-characterized-as-pseudoscience-20260505-13
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-13.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
The Center for Applications of Psychological Type claims that the MBTI is scientifically supported, but most of the research on it is done through its own journal, Journal of Psychological Type, raising questions of bias. Results are said to follow the Barnum effect. Neuro-linguistic programming – an approach to communication, personal development, and psychotherapy created in the 1970s. The title refers to a stated connection between the neurological processes ("neuro"), language ("linguistic") and behavioral patterns that have been learned through experience ("programming") and can be organized to achieve specific goals in life. According to certain neuroscientists psychologists and linguists, NLP is unsupported by current scientific evidence, and uses incorrect and misleading terms and concepts. Reviews of empirical research on NLP indicate that NLP contains numerous factual errors, and has failed to produce reliable results for the claims for effectiveness made by NLP's originators and proponents. According to Devilly, NLP is no longer as prevalent as it was in the 1970s and 1980s. Criticisms go beyond the lack of empirical evidence for effectiveness; critics say that NLP exhibits pseudoscientific characteristics, title, concepts and terminology. NLP is used as an example of pseudoscience for facilitating the teaching of scientific literacy at the


id: list-of-topics-characterized-as-pseudoscience-20260505-14
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-14.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
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parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
=== Racial theories === Scientific racism – claim that scientific evidence shows the inferiority or superiority of certain races. Aryanism – the claim that there is a distinct "Aryan race" that is superior to other putative races was an important tenet of Nazism and "the basis of the German government policy of exterminating Jews, Gypsies, and other 'non-Aryans.'" Drapetomania was a conjectural mental illness that, in 1851, American physician Samuel A. Cartwright hypothesized as the cause of enslaved Africans fleeing captivity. It has since been debunked as pseudoscience and part of the edifice of scientific racism. Melanin theory – belief founded in the distortion of known physical properties of melanin, a natural polymer, that posits the inherent superiority of dark-skinned people and the essential inhumanity and inferiority of light-skinned people. Turkish History Thesis – the belief that Turks from Central Asia migrated and brought civilization to China, India, the Middle East, and Europe. Eugenics – As a movement, eugenics was associated with pseudoscience including pseudoscientific journals and professional societies. This is to be contrasted with the common and scientifically accepted practice of selective breeding. === Sociology === Alpha and beta male – pseudoscientific terms for men derived from alpha and


id: list-of-topics-characterized-as-pseudoscience-20260505-15
file: data/en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience-15.md
category: reference
title: List of topics characterized as pseudoscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_topics_characterized_as_pseudoscience
date_saved: 2026-05-05T07:51:15.339434+00:00
instance: kb-cron
parent: list-of-topics-characterized-as-pseudoscience-20260505-0
summary:
Animal mutilations – cases of animals, primarily domestic livestock, with seemingly inexplicable wounds. These wounds have been said to be caused by extraterrestrials, cults, covert government organizations, or cryptids such as el chupacabra, when in fact most such cases were found to be caused by natural predation. An aura or human energy field is, according to New Age beliefs, a colored emanation said to enclose a human body or any animal or object. In some esoteric positions, the aura is described as a subtle body. Psychics and holistic medicine practitioners often claim to have the ability to see the size, color and type of vibration of an aura. In New Age alternative medicine, the human aura is seen as a hidden anatomy that affects the health of a client, and is often understood to be composed of centers of vital force called chakra. Such claims are not supported by scientific evidence and are pseudoscience. When tested under controlled experiments, the ability to see auras has not been shown to exist. Channeling – communication of information to or through a person allegedly from a spirit or other paranormal entity. Crop circles – geometric designs of crushed or knocked-over crops created in


