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

The term quantum advantage refers to quantum’s doing something “cheaper, faster, or more accurately” than classical computers, by Gambetta’s definition.

From MarketWatch • May 22, 2026

They do, however, suggest that the current definition of B12 deficiency may be too blunt for brain health.

From Science Daily • May 22, 2026

If anyone needs a definition for what grinding means in sports, sophomore Carlos Acuna’s performance on Wednesday at Cal State Northridge provided the answer.

From Los Angeles Times • May 21, 2026

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

From BBC • May 19, 2026

I wrote this definition in my notes, but I didn’t understand it.

From "Educated" by Tara Westover

Related Words

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