function
Americannoun
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the kind of action or activity proper to a person, thing, or institution; the purpose for which something is designed or exists; role.
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any ceremonious public or social gathering or occasion.
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a factor related to or dependent upon other factors.
Price is a function of supply and demand.
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Mathematics.
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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.
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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.
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a set of ordered pairs in which none of the first elements of the pairs appears twice.
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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
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Geometry.
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a formula expressing a relation between the angles of a triangle and its sides, as sine or cosine.
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Grammar.
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the grammatical role a linguistic form has or the position it occupies in a particular construction.
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the grammatical roles or the positions of a linguistic form or form class collectively.
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Sociology. the contribution made by a sociocultural phenomenon to an ongoing social system.
verb (used without object)
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to perform a specified action or activity; work; operate.
The computer isn't functioning now. He rarely functions before noon.
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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.
noun
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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
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an official or formal social gathering or ceremony
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a factor dependent upon another or other factors
the length of the flight is a function of the weather
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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)
verb
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to operate or perform as specified; work properly
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(foll by as) to perform the action or role (of something or someone else)
a coin may function as a screwdriver
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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.
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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.
Other Word Forms
Derived Forms
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prefunctionnoun
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subfunctionnoun
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superfunctionnoun
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refunctionverb (used without object)
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functionlessadjective
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interfunctionadjective
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multifunctionadjective
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nonfunctioningadjective
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overfunctioningadjective
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unfunctioningadjective
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well-functioningadjective
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
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functionsimple
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functionssimple
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have functionedperfect
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has functionedperfect
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am functioningprogressive
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are functioningprogressive
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is functioningprogressive
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have been functioningperfect progressive
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has been functioningperfect progressive
Past
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functionedsimple
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had functionedperfect
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was functioningprogressive
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were functioningprogressive
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had been functioningperfect progressive
Future
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."
Vocabulary lists containing function
TEKS ELAR Academic Vocabulary List (5th-7th grades)
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The SAT: Language of the Test, List 6
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The Language of Standardized Tests, List 4
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
A sport cannot function seriously on a world scale without such conformity, and a World Cup - launched in 1963 and contested every four years since - needed that.
From BBC ● Jul. 23, 2026
“We apparently accept them as a function of aging, when they’re really about bad design.”
From The Wall Street Journal ● Jul. 22, 2026
Autophagy is a natural recycling process that allows cells to remove damaged material and maintain normal function.
From Science Daily ● Jul. 21, 2026
Archer’s primary focus is the development of commercial air taxis that it says will function like flying Ubers to shuttle passengers over congested cities.
From Los Angeles Times ● Jul. 21, 2026
That genes could be regulated—i.e., turned “on” and “off” by particular cues—deepened the understanding of how genes function in time and space to specify the unique features of distinct cells.
From "The Gene" by Siddhartha Mukherjee
The board approves the EDC’s annual budget but when it comes to approving actual projects, it largely functions as a final rubber stamp.
From The Wall Street Journal ● Jul. 23, 2026
But EA barristers said it had a general power to bring private prosecutions, and alternatively that allegations of conspiracy to defraud were connected to its functions.
From BBC ● Jul. 22, 2026
Some of those host proteins previously had poorly understood functions.
From Science Daily ● Jul. 21, 2026
Isabella Wanningen, 22, a computer science student who worked on the energy functions of the car, said the vehicle's name encapsulated the team's hopes for the impact.
From Barron's ● Jul. 21, 2026
“They’re watching us in here, too? Are we allowed to use the bathroom privately, or are they surveilling our bodily functions as well?”
From "Internment" by Samira Ahmed
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
They were also building out an empire, and that empire functioned by top-down tyrannical rule.
From Slate ● Jul. 3, 2026
The conflict has functioned as an accelerated stress test, compressing years of operational learning into months and validating or refuting assumptions about real-world system performance.
From MarketWatch ● Jun. 29, 2026
In this framework, Earth functioned as a natural "all-in-one" chemistry laboratory operating over immense periods of time.
From Science Daily ● Jun. 10, 2026
His mind functioned without flaw, trying to calculate his surroundings and predicament.
From "The Maze Runner" by James Dashner
Research has linked synchronized movement with social bonding and increased pain thresholds, while studies of dance and movement therapy have found benefits for depression, anxiety and interpersonal functioning.
From Salon ● Jul. 20, 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
He aimed to get the best talent in the country in one functioning and balanced starting 11.
From BBC ● Jul. 16, 2026
The remainder is used to produce new roots and leaves or is oxidized to keep living cells functioning through the winter.
From Science Daily ● Jul. 9, 2026
Yet the nature of many of the chemicals used against insects, rodents, and weeds is such that they may strike directly at this system, disrupting its beautifully functioning mechanism.
From "Silent Spring" by Rachel Carson
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.