functions

IPA/ˈfʌŋk.ʃən/
KK[fˈʌŋkʃənz]IPA/ˈfʌŋk.ʃən/

functions — noun

  • functionssingular
  • functionsesplural

1. the purpose that something is designed to serve, or the job that a person is exp

1.nounB1
Definition

the purpose that something is designed to serve, or the job that a person is expected to carry out in a particular situation

Example

The main function of the heart is to pump blood throughout the entire body.

collocation: main function of [organ]

One of a teacher's most important functions is helping students learn to think for themselves.

Common collocations
  • main function
  • primary function
  • vital function
  • function of
Synonyms
  • role

    broader — can describe social position or expected behaviour, not just designed purpose

  • purpose

    more general; emphasizes the intended goal rather than the ongoing job

  • duty

    specifically about moral or legal obligation, often for a person's job

Usage Note

Frequently used with possessive adjectives (her function, its function) or in constructions with 'of' (the function of…).

Common Mistakes

The function of a knife to cut things.
The function of a knife is to cut things.
The verb 'is' must connect the subject to the infinitive of purpose.

2. a large formal social event or official ceremony where many people gather to cel

2.nounB2
Definition

a large formal social event or official ceremony where many people gather to celebrate, raise money, or network

Example

The wedding function was held in a grand hotel with more than two hundred guests.

collocation: wedding/charity/diplomatic function

The mayor attended a charity function to help raise money for the local library.

Common collocations
  • charity function
  • social function
  • diplomatic function
  • formal function
Synonyms
  • event

    wider meaning — includes informal occasions, not just formal ones

  • ceremony

    more specific to official rituals rather than social gatherings

  • gathering

    more general and less formal than function

Common Mistakes

They had a small family function for dinner last night.
They had a small family gathering for dinner last night.
'Function' implies a formal event; use 'gathering' or 'get-together' for casual occasions.

3. how something behaves or does its job when it is being used — for example, the j

3.nounB2
Definition

how something behaves or does its job when it is being used — for example, the job that an organ, machine, or individual component performs within a larger system

Example

Eli studied the function of each part in the car engine before the exam.

collocation: function of [body part/machine part]

The doctor carefully explained the function of the kidneys to her worried patient.

Common collocations
  • function of
  • bodily functions
  • normal function
  • proper function
Synonyms
  • operation

    focuses on the process of working; less natural with possessive ('the operation of the heart')

  • working

    more informal; common in spoken English

  • action

    emphasises the movement or activity involved, not the overall role

4. a named set of instructions in a computer program that performs a specific task

4.nounB2
Definition

a named set of instructions in a computer program that performs a specific task and can be used more than once in the program

Example

The programmer wrote a function that sorts all the names in alphabetical order.

grammar: call/define/write a function

You can call this function whenever you need to calculate the total cost.

Common collocations
  • call a function
  • define a function
  • write a function
  • search function
Synonyms
  • procedure

    similar but often implies no return value; more common in older programming contexts

  • routine

    less precise; can mean any repeated set of actions, not just in computing

  • subroutine

    more technical; commonly used in assembly and older languages

Usage Note

Common verbs used with this sense: call, define, write, execute, use. In many programming languages a function can accept input values and return an output.

Common Mistakes

I need to create a function for calculate the total.
I need to create a function to calculate the total.
Use the infinitive form (to + verb), not 'for + verb', after 'function'.

5. a result or situation that is directly produced by another factor or condition a

5.nounC1
Definition

a result or situation that is directly produced by another factor or condition and changes when that factor changes

Example

The success of the event is a function of how well the whole team prepares.

grammar: [noun] is a function of [noun]

In economics, the price of a product is a function of supply and demand.

Common collocations
  • function of
  • a function of
Synonyms
  • result

    simpler but less precise — does not imply a causal dependency

  • consequence

    suggests inevitability; stronger causal link than function

  • product

    formal; often used in economics and social sciences

Usage Note

Almost always appears in the pattern '[thing] is a function of [factor]'. Rarely used outside formal or academic writing.

6. in mathematics, a relationship where each input number corresponds to exactly on

6.nounB2
Definition

in mathematics, a relationship where each input number corresponds to exactly one output number, often written as f(x) = something

Example

Joshua learned how to graph a linear function on the coordinate plane in class.

grammar: graph/plot a function; linear/quadratic function

The function f of x equals x squared produces a curved shape called a parabola.

Common collocations
  • linear function
  • quadratic function
  • graph a function
  • value of the function
Synonyms
  • mapping

    more technical; used in advanced mathematics to emphasise the correspondence between sets

  • transformation

    focuses on changing inputs into outputs; common in geometry and algebra

Usage Note

Distinguish from noun/4 (COMPUTER PROCESS): in mathematics the function is a pure relation between numbers, not a set of code instructions. Also avoid confusing with noun/5 (DEPENDENT RESULT): the mathematical sense is strictly formal and quantifiable.

Common Mistakes

❌ 'This is not a function because one input gives you two outputs.' — This statement is correct; a function must have exactly one output per input.

functions — verb

Word family

Synonym discussion

Sense: verb/1

'Work' is the most common and general word — it covers everything from a simple tool to a complex organisation ('the printer still works'). 'Function' is more formal and often suggests that something is doing its job adequately but not necessarily smoothly ('the system functions despite the old wiring'). 'Operate' implies controlled action, often by a person or according to a procedure ('the pilot operates the controls'). 'Run' suggests continuous activity, usually of a machine or an organisation ('the factory runs 24 hours a day'). For a learner, use 'work' in everyday conversation, 'function' in formal writing, and 'operate' or 'run' when you want to emphasise how something is managed. For example: 'The coffee machine still works.' / 'The new department functions well under the current manager.' / 'She operates the forklift carefully.' / 'He runs a small bakery in the neighbourhood.'

function ↗work ↗operate ↗run ↗

Common collocations

Nouns

Adverbs

Phrases

  • function as
  • function of
  • in function

Prepositions

Etymology

LatinFrenchEnglish

The word 'function' entered English in the 16th century from French 'fonction', which came from Latin 'functio' meaning 'performance, execution'. The Latin root 'fungi' means 'to perform, to carry out'. The mathematical sense developed in the late 17th century as mathematicians sought a word for a quantity that depends on another. The computing sense appeared in the mid-20th century with the rise of programming languages.

First known use

1533

1533, in the meaning defined at sense 2 Verb