functional

American  

[fuhngk-shuh-nl] / ˈfʌŋk ʃə nl /

adjective

1. of or relating to a function or functions.

   functional difficulties in the administration.

2. capable of operating or functioning.

   When will the ventilating system be functional again?

3. having or serving a utilitarian purpose; capable of serving the purpose for which it was designed.

   functional architecture; a chair that is functional as well as decorative.

4. Also functionalistic (of a building or furnishing) constructed or made according to the principles of functionalism or primarily as a direct fulfillment of a material need.

5. Medicine/Medical. without a known organic cause or structural change.

   a functional disorder.

6. pertaining to an algebraic operation.

   a functional symbol.

7. Linguistics. (of linguistic analysis, language teaching, etc.) concerned with the communicative role of language rather than, in addition to, or as the framework for its formal structure.

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noun

1. Mathematics. a function that has a domain whose elements are functions, sets, or the like, and that assumes numerical values.

functional British  

/ ˈfʌŋkʃənəl /

adjective

1. of, involving, or containing a function or functions

2. practical rather than decorative; utilitarian

   functional architecture

3. capable of functioning; working

4. med affecting a function of an organ without structural change

5. psychol

   1. relating to the purpose or context of a behaviour

   2. denoting a psychosis such as schizophrenia assumed not to have a direct organic cause, like deterioration or poisoning of the brain Compare organic psychosis

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noun

1. maths a function whose domain is a set of functions and whose range is a set of functions or a set of numbers

Other Word Forms

Derived Forms

• subfunctionally
  adverb
• hyperfunctionally
  adverb
• semifunctionally
  adverb
• hyperfunctional
  adjective
• functionally
  adverb
• superfunctional
  adjective
• unfunctionally
  adverb
• prefunctional
  adjective
• subfunctional
  adjective
• unfunctional
  adjective
• nonfunctionally
  adverb
• functionality
  noun
• multifunctional
  adjective
• semifunctional
  adjective
• nonfunctional
  adjective

Etymology

Origin of functional

First recorded in 1625–35; function + -al ¹

Explanation

Use the adjective functional to describe something that is made to do a specific job, such as the functional alarm clock feature on a digital stopwatch. The word functional comes from the Latin word functionem, meaning "performance, execution." It can also describe whether something is working properly. This is what shoppers at a garage sale want to be sure of before they leave with an old television — they plug it in to make sure it's functional. In this case the opposite of functional is useless.

Example Sentences

The experimental findings were supported by first-principles calculations based on density functional theory, performed by a theoretical team led by Dr. Maia G. Vergniory of the Donostia International Physics Center and Université de Sherbrooke.

From Science Daily • Jun. 5, 2026

Using advanced transcriptomic analyses and functional studies in both mouse models and human samples, the researchers examined what happens when cancer cells lose MHC I expression.

From Science Daily • Jun. 4, 2026

Voters are “hungry for a different future for this city — one that is affordable, functional, creative, and safe,” Raman said in a statement.

From Los Angeles Times • Jun. 1, 2026

GSK said the drug has potential to redefine the treatment of a disease for which the current standard of care typically requires lifelong therapy and achieves functional cure rates of less than 1%.

From The Wall Street Journal • May 28, 2026

Leonardo’s drawing is clear enough for a model of the machine to have been built and demonstrated to be functional.

From "The Invention of Science" by David Wootton

Related Words

• practical
• useful
• utilitarian