Unit may refer to:

General measurement

Unit of measurement A unit of measurement, or unit of measure, is a definite magnitude (mathematics), magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other qua ...

, a definite magnitude of a physical quantity, defined and adopted by convention or by law **

International System of Units The International System of Units, internationally known by the abbreviation SI (from French ), is the modern form of the metric system and the world's most widely used system of measurement. It is the only system of measurement with official s ...

(SI), modern form of the metric system **

English units English units were the units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxons, Anglo-Saxon and Ancient Roman units of measurement, Roman systems of units. V ...

, historical units of measurement used in England up to 1824 **

Unit of length A unit of length refers to any arbitrarily chosen and accepted reference standard for measurement of length. The most common units in modern use are the metric units, used in every country globally. In the United States the U.S. customary un ...

Science and technology

Physical sciences

* Natural unit, a physical unit of measurement * Geological unit or rock unit, a volume of identifiable rock or ice *

Astronomical unit The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its m ...

, a unit of length roughly between the Earth and the Sun

Chemistry and medicine

* Equivalent (chemistry), a unit of measurement used in chemistry and biology * Unit, a vessel or section of a

chemical plant A chemical plant is an industrial process plant that manufactures (or otherwise processes) chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transfor ...

* Blood unit, a measurement in blood transfusion *

Enzyme unit The enzyme unit, or international unit for enzyme (symbol U, sometimes also IU) is a unit of enzyme's catalytic activity. 1 U (μmol/min) is defined as the amount of the enzyme that catalyzes the conversion of one micro mole of substrate pe ...

, a measurement of active enzyme in a sample *

International unit In pharmacology, the international unit (IU) is a unit of measurement for the effect or biological activity of a substance, for the purpose of easier comparison across similar ''forms'' of substances. International units are used to quantify vi ...

, a unit of measurement for nutrients and drugs

Mathematics

* Unit number, the number 1 * Unit,

identity element In mathematics, an identity element or neutral element of a binary operation is an element that leaves unchanged every element when the operation is applied. For example, 0 is an identity element of the addition of real numbers. This concept is use ...

Unit (ring theory) In algebra, a unit or invertible element of a ring is an invertible element for the multiplication of the ring. That is, an element of a ring is a unit if there exists in such that vu = uv = 1, where is the multiplicative identity; the ele ...

, an element that is invertible with respect to ring multiplication * Unit, a

tuple In mathematics, a tuple is a finite sequence or ''ordered list'' of numbers or, more generally, mathematical objects, which are called the ''elements'' of the tuple. An -tuple is a tuple of elements, where is a non-negative integer. There is o ...

of length 0; an empty tuple *

Statistical unit In statistics, a unit is one member of a set of entities being studied. It is the main source for the mathematical abstraction of a "random variable". Common examples of a unit would be a single person, animal, plant, manufactured item, or countr ...

, a data point on which statistical analysis is performed * Unit angle, a full turn equal to an angle of 1 *

Unit circle In mathematics, a unit circle is a circle of unit radius—that is, a radius of 1. Frequently, especially in trigonometry, the unit circle is the circle of radius 1 centered at the origin (0, 0) in the Cartesian coordinate system in the Eucli ...

, a circle with a radius of length 1 *

Unit cube A unit cube, more formally a cube of side 1, is a cube whose sides are 1 unit long.. See in particulap. 671. The volume of a 3-dimensional unit cube is 1 cubic unit, and its total surface area is 6 square units.. Unit hypercube The term '' ...

, a cube with sides of length 1 *

Unit fraction A unit fraction is a positive fraction with one as its numerator, 1/. It is the multiplicative inverse (reciprocal) of the denominator of the fraction, which must be a positive natural number. Examples are 1/1, 1/2, 1/3, 1/4, 1/5, etc. When a ...

, a reciprocal of a positive integer * Unit imaginary number, square root of negative 1

(\sqrt)

Unit impulse Unit may refer to: General measurement * Unit of measurement, a definite magnitude of a physical quantity, defined and adopted by convention or by law **International System of Units (SI), modern form of the metric system **English units, histo ...

, an impulse of height 1 *

Unit interval In mathematics, the unit interval is the closed interval , that is, the set of all real numbers that are greater than or equal to 0 and less than or equal to 1. It is often denoted ' (capital letter ). In addition to its role in real analysi ...

, an interval of distance 1 *

Unit matrix In linear algebra, the identity matrix of size n is the n\times n square matrix with ones on the main diagonal and zeros elsewhere. It has unique properties, for example when the identity matrix represents a geometric transformation, the obje ...

, a diagonal matrix such that all elements on the main diagonal are 1 and all the others are zero *

Unit round-off Machine epsilon or machine precision is an upper bound on the relative approximation error due to rounding in floating point number systems. This value characterizes computer arithmetic in the field of numerical analysis, and by extension in the ...

, an upper bound on the relative error due to rounding in floating point *

Unit set Unit may refer to: General measurement * Unit of measurement, a definite magnitude of a physical quantity, defined and adopted by convention or by law **International System of Units (SI), modern form of the metric system **English units, histo ...

, a singleton, a set with exactly 1 element *

Unit sphere In mathematics, a unit sphere is a sphere of unit radius: the locus (mathematics), set of points at Euclidean distance 1 from some center (geometry), center point in three-dimensional space. More generally, the ''unit -sphere'' is an n-sphere, -s ...

, a sphere with a radius of length 1 *

Unit square In mathematics, a unit square is a square whose sides have length . Often, ''the'' unit square refers specifically to the square in the Cartesian plane with corners at the four points ), , , and . Cartesian coordinates In a Cartesian coordinat ...

, a square with sides of length 1 *

Unit vector In mathematics, a unit vector in a normed vector space is a Vector (mathematics and physics), vector (often a vector (geometry), spatial vector) of Norm (mathematics), length 1. A unit vector is often denoted by a lowercase letter with a circumfle ...

, a vector with length equal to 1 *

Unit type In the area of mathematical logic and computer science known as type theory, a unit type is a type that allows only one value (and thus can hold no information). The carrier (underlying set) associated with a unit type can be any singleton set. ...

, a type allowing only one value in type theory

Computing

Central processing unit A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary Processor (computing), processor in a given computer. Its electronic circuitry executes Instruction (computing), instructions ...

, the electronic circuitry within a computer that carries out the instructions of a computer program * GNU Units, a software program for unit conversion * Rack unit, a unit of measure most commonly used to define the size of certain computing equipment *

Unit testing Unit testing, component or module testing, is a form of software testing by which isolated source code is tested to validate expected behavior. Unit testing describes tests that are run at the unit-level to contrast testing at the Integration ...

, a method by which individual units of source code are tested

Business

Stock keeping unit In inventory management, a stock keeping unit (abbreviated as SKU, pronounced or ) is the unit of measure in which the stocks of a material are managed. It is a distinct type of item for sale, purchase, or tracking in inventory, such as a produ ...

, a discrete inventory management construct *

Strategic business unit A strategic business unit (SBU) in business strategic management, is a profit center which focuses on product offering and market segment. SBUs typically have a discrete marketing plan, analysis of competition, and marketing campaign, even though ...

, a profit center which focuses on product offering and market segment *

Unit of account In economics, unit of account is one of the functions of money. A unit of account is a standard numerical monetary unit of measurement of the market value of goods, services, and other transactions. Also known as a "measure" or "standard" of ...

, a monetary unit of measurement * Unit coin, a small coin or medallion (usually military), bearing an organization's insignia or emblem * Work unit, the name given to a place of employment in the People's Republic of China * Telephone card unit. When bought contains a certain amount of units, which make up their own currency for making telephone calls, that may not necessarily correspond to the monetary cost of the actual telephone card.

Military

* Active service unit, the former Provisional Irish Republican Army cell *

Military unit Military organization ( AE) or military organisation ( BE) is the structuring of the armed forces of a state so as to offer such military capability as a national defense policy may require. Formal military organization tends to use hiera ...

, an homogeneous military organization whose administrative and command functions are self-contained * Sayeret Matkal (The Unit), the Israeli special forces unit

Arts and entertainment

* UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a discrete piece of action (or beat) in a theatrical presentation

Music

Album-equivalent unit The album-equivalent unit, or album equivalent, often shortened to just unit, is a sales metric in the music industry that defines the number of streaming media, songs streamed and music download, songs downloaded equal to one Record sales, tradi ...

, a unified measure of music sales across traditional and digital formats * ''Unit'' (album), 1997 album by the Australian band Regurgitator *

The Units Units were an American synthpunk band that was founded in San Francisco in 1978. It was active until 1984. They were one of America's earliest electronic New wave music, new wave bands, and have been cited (along with The Screamers and Suicide ...

, a synthpunk band

Television

* '' The Unit'', an American television series * '' The Unit: Idol Rebooting Project'', South Korean reality TV survival show

Other uses

* Unit of alcohol, a measure of the volume of pure ethanol in an alcoholic beverage *

Unit (housing) A housing unit, or dwelling unit (at later mention, often abbreviated to ''unit''), is a structure or the part of a structure or the space that is used as a home, residence, or sleeping place by one person or more people who maintain a common hous ...

, a self-contained suite of rooms within a set of similar dwellings * Unit,

course credit A course credit is a measure of the size of an educational course, often used to determine whether the requirements for an award have been met, to facilitate transfer between institutions, or to enhance intercomparability of qualifications. Credit ...

at a school or other educational institution *

Multiple unit A multiple-unit train (or multiple unit (MU)) is a self-propelled train composed of one or more Coach (rail), carriages joined, and where one or more of the carriages have the means of propulsion built in. By contrast, a locomotive-hauled ...

, self-propelled train carriage capable of coupling other units of the same type * Head unit, a component of a stereo system mounted inside of a vehicle * Unit (Cristian Fleming) (born 1974), electronic musician based in New York City *

Unit (Norway) Unit, which labels itself as the Norwegian "directorate for ICT and joint services in higher education and research", is the within the Ministry of Education and Research which provides governance of and access to shared information and commun ...

, a government directorate