Unit 731, a covert medical experiment unit of the Imperial Japanese Army, which researched biological warfare through human experimentation during the Second Sino-Japanese War (1937-1945) and World War II

In biochemistry, unit is the measure of enzyme activity.

G-Unit, a hip-hop music group

United Nations Intelligence Taskforce, a fictional entity in the Doctor Who television series

Units of measurement, a fundamental quantity of measurement

The Unit, a television series

Root of unity, a complex number, a power of which is 1

In a 19-inch rack a rack unit is a standard height of 1.75 inches

Matthew Hayden, Australian cricketer (alternate nickname)

Multiple unit, a passenger train whose carriages have their own motors

Imaginary unit, i, whose square is -1

A unit can refer to a self-contained section of a building (or maybe a structure such as a cabin) meant to be rented or otherwise occupied by a party, such as an apartment or business suite. See Apartment.

Unit vector, a vector with length 1

Unit 101, an Israeli special operations unit

Units conversion by factor-label, a widely used approach for performing unit conversions

Unit of alcohol, 10 millilitres of pure ethanol in the UK

Unit (album), an indie pop album by the Australian band Regurgitator

Unit circle, the circle with radius 1 centered at the origin

In filmmaking, see second unit.

Unit (ring theory), an element that is invertible with respect to ring multiplication

Units (Unix), a command-line computer program that does unit conversion

Unit interval, the interval of all real numbers between 0 and 1

Unit type, a type that allows only one value

A Strategic business unit

Unit (housing), in Australia/New Zealand - a self-contained suite of rooms within a set of similar dwellings.

Unit of action, a discrete piece of action (or beat) in a theatrical presentation

In chemical engineering, a unit is a (usually) large vessel or section of a plant in which a unit operation goes on. See Chemical plant#Chemical processes.

In category theory, there is a natural transformation called the unit from the identity functor to the composition of two adjoint functors