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• unit
  unit

  noun

  a single thing or person.
• Unit.
  Unit.

  abbreviation

  Unitarian.

unit

¹ American  

[yoo-nit] / ˈyu nɪt /

noun

1. a single thing or person.

2. any group of things or persons regarded as an entity.

   They formed a cohesive unit.

3. one of the individuals or groups that together constitute a whole; one of the parts or elements into which a whole may be divided or analyzed.

4. one of a number of things, organizations, etc., identical or equivalent in function or form.

   a rental unit;

   a unit of rolling stock.

5. any magnitude regarded as an independent whole; a single, indivisible entity.

6. Also called dimension.  any specified amount of a quantity, as of length, volume, force, momentum, or time, by comparison with which any other quantity of the same kind is measured or estimated.

7. the least positive integer; one.

8. Also called unit's place. 

   1. (in a mixed number) the position of the first digit to the left of the decimal point.

   2. (in a whole number) the position of the first digit from the right of the decimal point.

9. a machine, part, or system of machines having a specified purpose; apparatus.

   a heating unit.

10. Education. a division of instruction centering on a single theme.

11. Military. an organized body of soldiers, varying in size and constituting a subdivision of a larger body.

12. Medicine/Medical.

    1. the measured amount of a substance necessary to cause a certain effect; a clinical quantity used when a substance cannot be readily isolated in pure form and its activity determined directly.

    2. the amount necessary to cause a specific effect upon a specific animal or upon animal tissues.

13. Mathematics.

    1. an identity element.

    2. an element in a group, ring, etc., that possesses an inverse.

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Unit. ² American  

abbreviation

1. Unitarian.

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unit ¹ British  

/ ˈjuːnɪt /

noun

1. a single undivided entity or whole

2. any group or individual, esp when regarded as a basic element of a larger whole

3. a mechanical part or integrated assembly of parts that performs a subsidiary function

   a filter unit

4. a complete system, apparatus, or establishment that performs a specific function

   a production unit

5. a subdivision of a larger military formation

6. Also called: unit of measurement.  A standard amount of a physical quantity, such as length, mass, energy, etc, specified multiples of which are used to express magnitudes of that physical quantity

   the second is a unit of time

7. the amount of a drug, vaccine, etc, needed to produce a particular effect

8. a standard measure used in calculating alcohol intake and its effect

9. maths

   1. (usually plural) the first position in a place-value counting system, representing a single-digit number

      in the decimal system the number 27 has 7 units and 2 tens

   2. (modifier) having a value defined as one for the system

      unit vector

10. Also called: unit set.  maths logic a set having a single member

11. short for home unit

12. short for stock unit

13. a self-propelled railcar

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Unit. ² British  

abbreviation

1. Unitarian

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Other Word Forms

• interunit
  adjective
• multiunit
  adjective
• subunit
  noun
• superunit
  noun

Etymology

Origin of unit

Coined in 1570 by John Dee ( def. ) as a translation of Greek mónas (previously rendered as unity ); perhaps influenced by digit

Explanation

A unit is a single, whole part of something, like a building block. In math class, you might do a unit on algebra before you do another unit on geometry. Also, there are units of measurement, such as inches and miles. The word unit started out in math but has branched out to refer to any singular thing that is part of something larger. Each apartment in a building is a unit. A unit can also be a small group that fits into a larger social organization, like a military unit or a family unit. In all cases, a unit is a small, whole part of something bigger.

Example Sentences

The Southern California native also has been assigned to the restorative justice drug court and the Law Enforcement Accountability and Integrity Unit, where she consulted on police misconduct cases.

From Los Angeles Times • May 1, 2026

But the company expects output to increase to more than 90% of capacity within weeks, once the Residue Catalytic Cracking Unit restarts.

From The Wall Street Journal • Apr. 21, 2026

By 6 p.m., the fire was mapped at 141 acres with no containment, while multiple ground and air resources worked to get it under control, according to Cal Fire’s Riverside County Unit.

From Los Angeles Times • Apr. 17, 2026

The incident is being investigated by officers from the Metropolitan Police's Cybercrime Unit, after the force received a referral from the Federal Bureau of Investigation in the US.

From BBC • Apr. 7, 2026

Dan Dalgard, a doctor of veterinary medicine, was the consulting veterinarian at the Reston Primate Quarantine Unit.

From "The Hot Zone" by Richard Preston

Related Words

• crew
• entity
• group
• system