function

American  

[fuhngk-shuhn] / ˈfʌŋk ʃən /

noun

functions plural

1. the kind of action or activity proper to a person, thing, or institution; the purpose for which something is designed or exists; role.

2. any ceremonious public or social gathering or occasion.

3. a factor related to or dependent upon other factors.

   Price is a function of supply and demand.

4. Mathematics.

   1. Also called correspondence, map, mapping, transformation.  a relation between two sets in which one element of the second set is assigned to each element of the first set, as the expression y = x 2 ; operator.

   2. Also called multiple-value function.  a relation between two sets in which two or more elements of the second set are assigned to each element of the first set, as y 2 = x 2 , which assigns to every x the two values y = + x and y = − x.

   3. a set of ordered pairs in which none of the first elements of the pairs appears twice.

   4. a relationship in which an input value of a variable has a specifically calculated output value: for example, if the function of x is x 2 , the output will always be the square of whatever the value of x is. f, F

5. Geometry.

   1. a formula expressing a relation between the angles of a triangle and its sides, as sine or cosine.

   2. hyperbolic function.

6. Grammar.

   1. the grammatical role a linguistic form has or the position it occupies in a particular construction.

   2. the grammatical roles or the positions of a linguistic form or form class collectively.

7. Sociology. the contribution made by a sociocultural phenomenon to an ongoing social system.

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verb (used without object)

functions, present (3rd person singular) functioned, past participle, past functioning present participle

1. to perform a specified action or activity; work; operate.

   The computer isn't functioning now. He rarely functions before noon.

2. to have or exercise a function; serve.

   In earlier English the present tense often functioned as a future. This orange crate can function as a chair.

function British  

/ ˈfʌŋkʃən /

noun

1. the natural action or intended purpose of a person or thing in a specific role

   the function of a hammer is to hit nails into wood

2. an official or formal social gathering or ceremony

3. a factor dependent upon another or other factors

   the length of the flight is a function of the weather

4. Also called: map.   mapping.  maths logic a relation between two sets that associates a unique element (the value) of the second (the range) with each element (the argument) of the first (the domain): a many-one relation. Symbol: f( x ) The value of f( x ) for x = 2 is f(2)

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verb

1. to operate or perform as specified; work properly

2. (foll by as) to perform the action or role (of something or someone else)

   a coin may function as a screwdriver

function Scientific  

/ fŭngk′shən /

1. A relationship between two sets that matches each member of the first set with a unique member of the second set. Functions are often expressed as an equation, such as y = x + 5, meaning that y is a function of x such that for any value of x, the value of y will be 5 greater than x.

2. A quantity whose value depends on the value given to one or more related quantities. For example, the area of a square is a function of the length of its sides.

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function Cultural  

1. In mathematics, a quantity whose value is determined by the value of some other quantity. For example, “The yield of this field is a function of the amount of fertilizer applied” means that a given amount of fertilizer will yield an amount of whatever crop is growing.

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Other Word Forms

Derived Forms

• prefunction
  noun
• subfunction
  noun
• superfunction
  noun
• refunction
  verb (used without object)
• functionless
  adjective
• interfunction
  adjective
• multifunction
  adjective
• nonfunctioning
  adjective
• overfunctioning
  adjective
• unfunctioning
  adjective
• well-functioning
  adjective

Inflected Forms

Nouns

• functions
  plural

Participles

• functioning
  present
• functioned
  past

Conjugated Forms

Present

• function
  simple
• functions
  simple
• have functioned
  perfect
• has functioned
  perfect
• am functioning
  progressive
• are functioning
  progressive
• is functioning
  progressive
• have been functioning
  perfect progressive
• has been functioning
  perfect progressive

Past

• functioned
  simple
• had functioned
  perfect
• was functioning
  progressive
• were functioning
  progressive
• had been functioning
  perfect progressive

Future

• will function
  simple
• will have functioned
  perfect
• will be functioning
  progressive
• will have been functioning
  perfect progressive

Etymology

Origin of function

First recorded in 1525–35; from Latin functiōn- (stem of functiō ) “a performance, execution,” equivalent to funct(us) (past participle of fungī ) “performed, executed” + -iōn- -ion

Explanation

In the old "Schoolhouse Rock" song, "Conjunction junction, what's your function?," the word function means, "What does a conjunction do?" The famous design dictum "form follows function" tells us that an object's design should reflect what it does. Function is one of those words that gets used a lot and means lots of different things. It means what something does, but also what a person does, whether something or someone is doing what they should, and crazily enough, a big party. "Your function is to bring the senator coffee at the political function. He cannot function without it."

Example Sentences

See Examples For:

function functions functioned functioning

Tucked against the arugula, they function almost like an extremely unserious vinaigrette.

From Salon ● Jul. 30, 2026

If the markets correctly understand the Fed’s reaction function, then they can do some of the Fed’s work for it.

From The Wall Street Journal ● Jul. 30, 2026

Of course, this is not a new function of the stage.

From Salon ● Jul. 30, 2026

“Each item I collect has a certain energy from its previous function that carries over into its new use.”

From Los Angeles Times ● Jul. 27, 2026

That, after all, was the dealers’ stated function: middlemen.

From "The Big Short" by Michael Lewis

The FCC also added foreign-made inverters to the list -- devices that, among other functions, convert direct current from batteries or solar panels into standard alternating current, which can be used by the electrical grid.

From Barron's ● Jul. 28, 2026

Yet schools have many fixed costs, such as maintaining, repairing, heating and cooling school buildings, operating cafeterias and managing many administrative functions that cannot easily be scaled down when enrollment declines inevitably reduce funding.

From Salon ● Jul. 28, 2026

Following its spinoff of Honeywell Aerospace, Honeywell Technologies now functions as a pure-play automation company.

From The Wall Street Journal ● Jul. 23, 2026

Those capabilities are essential for creating buffers and memory functions in optical computers.

From Science Daily ● Jul. 22, 2026

Not only will they look different when written on a staff, but they will have different functions within a key and different relationships with the other notes of a piece of music.

From "Understanding Basic Music Theory" by Catherine Schmidt-Jones and Russel Jones

Married to the legendary Washington Post editor Ben Bradlee until his death in 2014, Quinn has functioned, at least since the 1980s, as the self-appointed spokeswoman of the nation’s permanent political establishment.

From Salon ● Jul. 21, 2026

Our vertebral column has evolved little from our four-legged, quadrupedal tree-dwelling ancestors, where it functioned primarily as a flexible beam for smooth movement from branch to branch, while also protecting the spinal cord.

From Science Daily ● Jul. 11, 2026

In another lawsuit, he claimed an arcade rigged its claw machines against players, alleging it functioned as “a casino for children.”

From Los Angeles Times ● Jul. 8, 2026

They were also building out an empire, and that empire functioned by top-down tyrannical rule.

From Slate ● Jul. 3, 2026

I had a small cell near our large one that functioned as a study, with a chair, desk, and bookshelves, where I could read and write during the day.

From "Long Walk to Freedom" by Nelson Mandela

It is Exhibit A. A guarantee that demands this much luck, money, and endurance before a court will enforce it has not been functioning as a guarantee.

From Slate ● Jul. 28, 2026

The firm said three nuclear reactors operating in the region at the time were functioning normally.

From Barron's ● Jul. 28, 2026

Senescence is a damaged, poorly functioning cellular state that becomes more common with age and is believed to contribute to neurodegeneration.

From Science Daily ● Jul. 24, 2026

Since then, it has maintained exports of grain and sunflower oil and kept its beach resorts functioning.

From The Wall Street Journal ● Jul. 19, 2026

It was her brain that wasn’t functioning properly.

From "A Tangle of Knots" by Lisa Graff

Related Words

• action
• activity
• affair
• behavior
• business
• duty
• exercise
• objective
• operation
• part
• power
• purpose
• responsibility
• role
• service
• situation
• task
• work