1an individual thing or person regarded as single and complete but which can also form an individual component of a larger or more complex whole:large areas of land made up of smaller unitsthe sentence as a unit of grammarthe family unit
a self-contained section in a building or group of buildings:one- and two-bedroom units
a department of an institution with a specific function:the intensive-care unit
a subdivision of a larger military grouping:he returned to Germany with his unit
a self-contained part of an educational course:students take three compulsory core units
a single manufactured item: [as modifier]:unit cost
British the smallest measure of investment in a unit trust.
2a device that has a specified function, especially one forming part of a complex mechanism:the gearbox and transmission unit
a piece of furniture or equipment for fitting with others like it or made of complementary parts:a sink unit
US a police car:he eased into his unit and flicked the siren on
3a quantity chosen as a standard in terms of which other quantities may be expressed:a unit of measurementfifty units of electricity
4the number one.
(units) the digit before the decimal point in decimal notation, representing an integer less than ten.
late 16th century (as a mathematical term): from Latin unus, probably suggested by digit