function

verb

functioned; functioning ˈfəŋ(k)-sh(ə-)niŋ 

intransitive verb

1

: to have a function : serve

a couch that also functions as a bed

an attributive noun functions as an adjective

2

: to carry on a function or be in action : operate

The new machine functions well.

an immune system functioning normally

Synonyms of function

• serve
• act
• work

Examples of function in a Sentence

The new machine functions well.

His bad health has prevented him from being able to function effectively in recent weeks.

Her heart now seems to be functioning normally.

The computer network is not yet fully functioning.

Recent Examples on the Web

The other loft, meanwhile, is similarly laid out, but without the desk, and can function as either a second bedroom or additional storage space, depending on the owner's needs. —New Atlas, 8 June 2026

Congress was never intended to function as an extension of the White House. —The Editorial Board, Chicago Tribune, 8 June 2026

The SpotOn Nova Edition is designed to function as both a containment system and a training tool. —Rachel Cortez, USA Today, 8 June 2026

Authorities said hospital operations had resumed and that major highways, markets and commercial centers were functioning normally by Monday. —ABC News, 8 June 2026

Word History

Etymology

First Known Use

1856, in the meaning defined at sense 1

Phrases Containing function

• a function of
• Bessel function
• circular function
• composite function
• cumulative distribution function
• density function
• discriminant function
• distribution function
• executive function
• exponential function
• function key
• function word
• hyperbolic function
• inverse function
• linear function
• logarithmic function
• power function
• probability density function
• probability function
• propositional function
• rational function
• sentential function
• step function
• trigonometric function

Rhymes for function

• junction
• unction
• adjunction
• compunction
• conjunction
• disjunction
• dysfunction
• injunction
• malfunction
• eigenfunction
• multifunction
• heterojunction

Kids Definition

function

1 of 2 noun

func·​tion ˈfəŋ(k)-shən 

1

: professional job or duties : occupation

2

a

: the particular purpose for which a person or thing is specially fitted or used or for which a thing exists

the function of a knife is cutting

b

: the natural or proper action of a bodily part in a living thing

the function of the heart

3

: a large important ceremony or social affair

4

a

: a mathematical relationship that assigns exactly one element of one set to each element of the same or another set

b

: something (as a quality, trait, or measurement) that is determined by or based on something else

height is a function of age in children

functionless

-ləs 

adjective

function

2 of 2 verb

functioned; functioning -sh(ə-)niŋ 

: to serve a certain purpose : work

Medical Definition

function

1 of 2 noun

func·​tion ˈfəŋ(k)-shən 

1

: any of a group of related actions contributing to a larger action

especially : the specific contribution of a bodily part to the processes necessary for life in an organism

The function of the kidneys is to filter waste from the blood.

see vital function

2

: characteristic behavior of a chemical compound due to a particular reactive unit

also : functional group

functionless

-ləs 

adjective

function

2 of 2 intransitive verb

functioned; functioning -sh(ə-)niŋ 

: to have a function

shivering functions to maintain the heat of the body