What is function? - Definition from WhatIs.com
Part of the Computing fundamentals glossary:

In information technology, the term function (pronounced FUHNK-shun ) has a number of meanings. It's taken from the Latin "functio" - to perform.

1) In its most general use, a function is what a given entity does in being what it is.

2) In C language and other programming, a function is a named procedure that performs a distinct service. The language statement that requests the function is called a function call . Programming languages usually come with a compiler and a set of "canned" functions that a programmer can specify by writing language statements. These provided functions are sometimes referred to as library routines . Some functions are self-sufficient and can return results to the requesting program without help. Other functions need to make requests of the operating system in order to perform their work.

3) In mathematics, a function is a relationship between two variables called the independent variable and the dependent variable. The dependent variable has at most one value for any specific value of the independent variable. A function is usually symbolized by a lowercase, italicized letter of the alphabet, followed by the independent variable in parentheses. For example, the expression y = f ( x ), read " y equals f of x ," means that a dependent variable y is a function of the independent variable x . Functions are often graphed, and they usually appear as lines or curves on a coordinate plane.

4) In a hardware device, a function is one complete physical movement that has a discernible consequence relative to the device's purposes. In a printer, for example, this might be a carriage return or a line feed.

This was last updated in September 2005
Posted by: Margaret Rouse

Related Terms


  • Turing test

    - In artificial intelligence (AI), the Turing Test is a method for determining whether or not a computer is capable of thinking like a human. (WhatIs.com)

  • telepresence

    - Telepresence is a sophisticated form of robotic remote control in which a human operator has a sense of being in a remote location so that the experience resembles virtual reality (VR). (WhatIs.com)

  • gravity wave (or gravitational wave)

    - A gravity wave (or gravitational wave) is a ripple in the curvature of the space-time continuum (the enmeshed combination of our three perceived physical dimensions, plus time) created by the movem... (WhatIs.com)


  • Computing fundamentals

    - Terms related to computer fundamentals, including computer hardware definitions and words and phrases about software, operating systems, peripherals and troubleshooting.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question. Find an Answer.Powered by ITKnowledgeExchange.com

Ask An IT Question

Get answers from your peers on your most technical challenges

Ask Question

Tech TalkComment



    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.