definition

American  

[def-uh-nish-uhn] / ˌdɛf əˈnɪʃ ən /

noun

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.

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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

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Other Word Forms

• definitional
  adjective
• definitionally
  adverb
• predefinition
  noun
• redefinition
  noun
• self-definition
  noun
• subdefinition
  noun

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.

Example Sentences

There’s no standard definition of a “carnivore diet,” but it generally means only eating animal-based foods like meat, seafood, eggs and full-fat dairy.

From MarketWatch • May 19, 2026

Another avenue Pratt put forward in an interview posted on YouTube is using the expanded definition of gravely disabled in a law championed and signed into law by Gov. Gavin Newsom in 2023.

From Los Angeles Times • May 19, 2026

It is possible that a few places could meet the heatwave definition during Friday, Saturday and Sunday.

From BBC • May 19, 2026

For nearly two decades, he had been the definition of sports anonymity—an interchangeable cog turning in the unforgiving machine that is professional baseball.

From The Wall Street Journal • May 15, 2026

But before I can share my issues with the technical definition of living, my thought pattern is interrupted by a sound.

From "A Rover's Story" by Jasmine Warga

Related Words

• answer
• explanation
• interpretation
• rationale
• solution
• translation