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definition

American  
[def-uh-nish-uhn] / ˌdɛf əˈnɪʃ ən /

noun

  • definitions
    plural
  1. the act of defining, or of making something definite, distinct, or clear.

    We need a better definition of her responsibilities.

  2. the formal statement of the meaning or significance of a word, phrase, idiom, etc., as found in dictionaries. An online dictionary resource, such as Dictionary.com, can give users direct, immediate access to the definitions of a term, allowing them to compare definitions from various dictionaries and stay up to date with an ever-expanding vocabulary.

  3. the condition of being definite, distinct, or clearly outlined.

    His biceps have great muscle definition.

  4. Optics. sharpness of the image formed by an optical system.

  5. Radio and Television. the accuracy of sound or picture reproduction.


definition British  
/ ˌdɛfɪˈnɪʃən /

noun

  1. a formal and concise statement of the meaning of a word, phrase, etc

  2. the act of defining a word, phrase, etc

  3. specification of the essential properties of something, or of the criteria which uniquely identify it

  4. the act of making clear or definite

  5. the state or condition of being clearly defined or definite

  6. a measure of the clarity of an optical, photographic, or television image as characterized by its sharpness and contrast

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Derived Forms

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Nouns

Etymology

Origin of definition

First recorded in 1350–1400; Middle English diffinicioun, from Old French diffinition, from Latin dēfīnītiōn- (stem of dēfīnītiō ), equivalent to dēfīnīt(us) ( see definite) + -iōn- noun suffix ( see -ion)

Explanation

A good definition explains concisely what something means. Dictionaries include definitions, even for the word definition! A definition precisely explains the fundamental state or meaning of something, often given formally as by lexicographers writing a dictionary or legislators writing laws. It can also refer to a sharply detailed image or concept — like how clear the picture is on a high-definition TV or how cut a Calvin Klein model's abs are.

Keep Reading on Vocabulary.com

Vocabulary lists containing definition

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:

But to have visible definition in your biceps, you have to put in the work.

From The Wall Street Journal ● Oct. 2, 2026

Much has been debated about when or whether this will happen, but neuroscientists like me and my colleagues can’t even truly agree on a definition of what consciousness is.

From The Wall Street Journal ● Sep. 30, 2026

Young people who end up playing in the NFL are, by definition, by far the fittest and strongest in their schools and colleges.

From MarketWatch ● Sep. 30, 2026

Its definition of "allurement" includes employment, free education at a religious institution, a promise of marriage, a "better lifestyle" and "divine healing".

From BBC ● Sep. 29, 2026

I am about to comment that this is because based on the technical definition, robots are not alive.

From "A Rover's Story" by Jasmine Warga

As California ushers in its certification label, she said, other states could adopt similar certification programs or develop their own definitions of ultraprocessed foods while a uniform federal definition is still in the works.

From Los Angeles Times ● Sep. 29, 2026

That meant LGBTQ+ and single people who historically had been shut out by definitions of infertility as a failure to conceive after six to 12 months of unprotected heterosexual intercourse.

From Los Angeles Times ● Sep. 27, 2026

"We ask that Australia clarify how exactly 'harm' and 'risks' shall be determined... ensuring these definitions do not encroach on protected speech," the US said in its submission.

From BBC ● Sep. 23, 2026

Which brings me back to my central-bank adviser and his answer about definitions.

From The Wall Street Journal ● Sep. 15, 2026

Plus copy out all the definitions for thirty- five words.

From "Frindle" by Andrew Clements

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