unit

1 of 2

noun

ˈyü-nət 

1

a

: the first and least natural number : one

b

: a single quantity regarded as a whole in calculation

2

: a determinate quantity (as of length, time, heat, or value) adopted as a standard of measurement

Feet and meters are both units of length.

: such as

a

: an amount of work used in education in calculating student credits

b

: an amount of a biologically active agent (such as a drug or antigen) required to produce a specific result see also international unit

3

a

: a single thing, person, or group that is a constituent of a whole

The family is the basic unit of society.

The search party broke up into smaller units.

b

: a part of a military establishment that has a prescribed organization (as of personnel and matériel)

c(1)

: a piece or complex of apparatus serving to perform one particular function

an air conditioning unit

(2)

: a set of similar pieces of furniture that are grouped or attached together

a built-in storage/wall unit

(3)

: an individual item of the products that a company makes or sells

d

: a part of a school course focusing on a central theme

finished the unit on the American Revolution

e

: a local congregation of Jehovah's Witnesses

f

: a small molecule especially when combined in a larger molecule

repeating units of a polymer

g

: an area in a medical facility and especially a hospital that is specially staffed and equipped to provide a particular type of care

an intensive care unit

h

: one of a number of apartment or residences in a building or complex

unit

2 of 2

adjective

: being, relating to, or measuring one unit

Examples of unit in a Sentence

Noun

The family is the basic unit of society.

The search party broke up into smaller units.

Their army unit guarded the border.

Feet and meters are units of length.

The dollar is the principal unit of American currency.

Recent Examples on the Web

Noun

Put simply, during the training process copies of these works are downloaded and stored before being broken down into discrete units called tokens. — Zoey Forbes, The Dial, 7 July 2026

Most office buildings have central air conditioning, so the system needs to be replaced with individual heating and cooling systems for each unit. — Samantha Delouya, CNN Money, 8 July 2026

Medina, then just 18, was booked into county jail and placed in a special observation unit after threatening to kill himself, banging his head and urinating in front of his counselor. — Jeff McDonald, San Diego Union-Tribune, 8 July 2026

The health department emphasized that residents cannot get it through drinking water, cooking or from using AC units, and Legionnaires' disease is not contagious. — Amethyst Martinez, USA Today, 8 July 2026

Word History

Etymology

Noun

back-formation from unity

First Known Use

Noun

1570, in the meaning defined at sense 1a

Adjective

1633, in the meaning defined above

Phrases Containing unit

• absolute unit
• astronomical unit
• atomic mass unit
• base unit
• British thermal unit
• canine unit
• central processing unit
• critical care unit
• electromagnetic unit
• imaginary unit
• intensive care unit
• international bitterness unit
• international unit
• inter-unit
• kitchen unit
• living unit
• monetary unit
• motor unit
• sub-unit
• unit cell
• unit character
• unit circle
• unit membrane
• unit rule
• unit train
• unit trust
• waste disposal unit

Kids Definition

unit

1 of 2 noun

ˈyü-nət 

1

a

: the first and smallest natural number : one

b

: a single quantity regarded as a whole in calculation

2

: a definite quantity (as of length, time, or value) used as a standard of measurement

the dollar is the unit of U.S. money

3

a

: a single thing or person or group that is a part of a whole

b

: a part or arrangement of parts performing one function

a train drawn by two diesel units

c

: a part of a school course with a central theme

unit

2 of 2 adjective

: being, relating to, or measuring one unit of

unit length

unit angle

Medical Definition

unit

noun

ˈyü-nət 

1

: an amount of a biologically active agent (as a drug or antigen) required to produce a specific result under strictly controlled conditions

a unit of penicillin

see international unit

2

: a small molecule especially when combined in a larger molecule

repeating units of a polymer

3

: an area in a medical facility and especially a hospital that is specially staffed and equipped to provide a particular type of care

an intensive care unit