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

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 * Blood unit, a measurement in blood transfusion * Enzyme unit, a measurement of active enzyme in a sample * International unit, 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), an element that is invertible with respect to ring multiplication * Unit, a tuple of length 0; an empty tuple * Statistical unit, a data point on which statistical analysis is performed * Unit angle, a full turn equal to an angle of 1 * Unit circle, a circle with a radius of length 1 * Unit cube, a cube with sides of length 1 * Unit fraction, a reciprocal of a positive integer * Unit imaginary number, square root of negative 1

(\sqrt)

* Unit impulse, an impulse of height 1 * Unit interval, an interval of distance 1 * Unit matrix, a diagonal matrix such that all elements on the main diagonal are 1 and all the others are zero * Unit round-off, an upper bound on the relative error due to rounding in floating point * Unit set, a singleton, a set with exactly 1 element * Unit sphere, a sphere with a radius of length 1 * Unit square, a square with sides of length 1 * Unit vector, a vector with length equal to 1 * Unit type, 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, a discrete inventory management construct * Strategic business unit, a profit center which focuses on product offering and market segment * Unit of account, 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, 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 self-contained suite of rooms within a set of similar dwellings * Unit, course credit at a school or other educational institution * Multiple unit, 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), a government directorate