function
Americannoun
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functions
plural
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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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functions,
present (3rd person singular)
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functioned,
past participle, past
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functioning
present participle
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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:
The treatment recruited the body's own immune cells, encouraged the formation of new blood vessels, supported changes in neural tissue, and improved motor function in the animals.
From Science Daily ● Sep. 4, 2026
The kidney continued to function for 271 days until it was removed in October that year.
From BBC ● Sep. 3, 2026
In a civil suit against Sanchez, Tole alleged that he suffered “severe permanent disfigurement, loss of function, other physical injuries, emotional distress, and other damages.”
From Los Angeles Times ● Sep. 3, 2026
Without water, its locks that lift and lower ships at the beginning and end of the journey would not function.
From Barron's ● Sep. 3, 2026
Study to look at possible benefits of musical training on brain function in young and old.
From "Music and the Child" by Natalie Sarrazin
He argued for an AI “for everyone” and pictured a future where the artificial intelligence tools his company was helping to create were integrated into the everyday functions of every single person on Earth.
From Salon ● Sep. 4, 2026
The difficulty is that these medications also interfere to varying degrees with other prostaglandins that perform important functions.
From Science Daily ● Sep. 3, 2026
Researchers also highlighted that manual notetaking serves important functions for clinicians in their reasoning and reflection on what the patient has said.
From BBC ● Sep. 3, 2026
The Houthis provided Jibril with a furnished apartment in San’a, the rebel-controlled Yemeni capital, according to the briefing, and he attended official functions.
From The Wall Street Journal ● Sep. 1, 2026
We were supposed to be attending firm functions together.
From "Becoming" by Michelle Obama
Although companies describe them as decision-support tools, she said they often functioned as "automated decision-making systems".
From BBC ● Aug. 5, 2026
For much of the past century, British politics functioned largely as a two-party system.
From Science Daily ● Aug. 2, 2026
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
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
WjJljZfL Come rain, come shine, come whatever, Bernabe Montoya had eyes that functioned just about like everybody else’s eyes in Milagro: they popped open, wide awake, each morning at 5:00 A.M.
From "The Milagro Beanfield War" by John Nichols
In a country better known for industrial farming, highly processed food and suspiciously long-lasting bread, Chuck Childers rises before dawn and trudges off to operate one of America's oldest functioning gristmills.
From Barron's ● Sep. 3, 2026
Importantly, however, bond markets aren’t in a panic mode and are functioning properly, analysts at Allianz Research said.
From The Wall Street Journal ● Sep. 2, 2026
After multiplying, the cells normally reverse that process and become mature, fully functioning liver cells again.
From Science Daily ● Aug. 31, 2026
The website was functioning normally as of Thursday, and the park is open.
From MarketWatch ● Aug. 28, 2026
It is a storehouse of many vitamins, some of which in turn contribute to its own proper functioning.
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.
