function

Pluralfunctions

Formsfunctions, functioning, functioned

1. 1
   what it doesnouncountable

   The purpose something serves or the job it is meant to do, including the role a custom or practice plays in keeping a society going.

   Nobody in the office could figure out the function of the extra button on the copier.

   Designers stripped away every part of the device that served no clear function.

   UsageCommon frames: serve a function, perform a function, the function of a part.

   Similarpurpose, role, use, job

   Note

   A function is what a thing actually does, not just what it was meant for. That puts it between purpose, which names an aim, and role, which names a place in a larger whole.

2. 2
   operateverbintransitive

   To operate as intended; to be in action and carry out its work.

   The backup generator functions only when the main power fails.

   Despite the damage, the engines continued to function normally.

   UsageOften with an adverb: function normally, function properly.

   Similarwork, operate, run, go (entry)

   Oppositemalfunction

3. 3
   organ activitynoununcountable

   The physiological activity carried out by an organ or body part.

   Doctors monitored her kidney function closely after the surgery.

   The drug gradually restores normal function to damaged nerve cells.

   UsageMost often led by the organ: kidney function, lung function. Doctors monitor or restore function.

   Similaractivity

   Oppositedysfunction

4. 4
   verbintransitive

   To serve as something; to fill a particular role or use.

   In a pinch, the rolled-up coat functions as a pillow.

   These dense hedges function as a natural barrier against the wind.

   UsageUsually followed by as and a noun phrase: the coat functions as a pillow. Serve as fits the same pattern.

   Similarserve

5. 5
   mathnouncountable

   A mathematical relation that pairs each element of one set with exactly one element of another.

   Every function assigns each input value a single output value.

   The teacher asked us to determine whether the relation was a function.

   Similarmap, mapping, transformation, operator

   Note

   Mathematicians write it f: X → Y, a rule taking each element of the domain X to one element of the codomain Y. The word that matters is exactly: a relation sending a single input to two outputs is not a function. Map and mapping are close synonyms in everyday mathematical prose. Transformation and operator usually signal particular kinds of function. Source

   Checked 30 Oct 2026 · 2 facts

   • The notation f: X → Y specifies a function with domain X and codomain Y. en.wikipedia.org
   • Each input must have exactly one output; a relation assigning two outputs to one input is not a function. openstax.org
6. 6
   nouncountable

   An organized official or social occasion.

   The charity hosts a formal function every winter.

   He shook hundreds of hands at the diplomatic function.

   Similaroccasion, affair

7. 7
   code routinenouncountable

   A block of code in a program that performs a particular task when called, often taking inputs and returning a result.

   She refactored the login code into a single reusable function.

   Each function in the module handles one part of the calculation.

   Similarroutine, procedure, subroutine, subprogram

   Note

   A programmer's function is looser than a mathematician's: it may take no arguments and may return nothing at all. It is still a callable block of code. Some languages shorten the keyword to func or fn. Subroutine and procedure cover nearly the same ground, and some programming communities prefer them for routines that return no result. Source

   Checked 30 Oct 2026 · 2 facts

   • A programming function may take no arguments and return no value. go.dev
   • Functions can be anonymous; a name is not required. docs.python.org
8. 8
   depends onnouncountable

   A result or outcome that depends on or stems from another thing.

   Crop yields are largely a function of rainfall and soil quality.

   The team's confidence proved to be a function of its recent wins.

   UsageUsually in the frame X is a function of Y, often softened with largely.

   Similarproduct, result, consequence, outcome

   Note

   It echoes the shape of the mathematical sense, one thing varying with another, but loosely and without equations. Source

   Checked 1 Nov 2026 · 1 fact

   • A mathematical function expresses dependence of one variable on another. columbia.edu
9. 9
   nouncountablebusiness

   One of the areas of an organization's work, such as finance or marketing, or the department that handles it.

   The company moved its entire HR function to a shared office in another state.

   Leaders from every function, including legal, operations, and sales, met to plan the merger.

   Similardepartment, division

   Note

   Large companies use this word to divide work by kind, so functions such as finance, HR, legal and IT stand apart from business units organized by product or region. The adjective follows it: a functional manager runs one function, and a cross-functional team draws people from several. Source

   Checked 1 Nov 2026 · 3 facts

   • Companies group work by function, with product and regional organization providing other bases for grouping. openstax.org
   • A functional manager manages a functional department. pmi.org
   • A cross-functional team includes people from different organizational functions. en.wikipedia.org
10. 10
    official rolenouncountable

    An official or professional position that a person occupies, or one of the duties that belong to it.

    She took on the function of department head last spring.

    The deputy assumed the function of mayor during the emergency.

    UsageOften plural for the duties of a post (perform the functions of a judge), or singular with of (the function of chair).

    Similarrole, office, occupation, part

    Note

    Here the Latin fungor, "to discharge" a duty, shows most plainly: a function in this sense is a post one carries out. Office and role overlap with it, but office names the position itself, while function stresses the work done in it. Source

    Checked 1 Nov 2026 · 1 fact

    • Function ultimately derives from Latin fungor, meaning to perform or discharge. en.wiktionary.org

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