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) ( definite ) + -iōn- noun suffix ( -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

So in that sense, what is “moral” in this situation can take on a variety of forms, depending on which definition of what is “right” is prioritized in your own mind.

From Los Angeles Times • Apr. 10, 2026

Two days later, legislators took up the Public Nuisance Reform Act, which proposes narrowing the definition of what could be considered a nuisance.

From Salon • Apr. 10, 2026

While there is no hard and fast definition of what constitutes a TACO, several Wall Street professionals who spoke with MarketWatch for this story agreed with our list of nine specific events.

From MarketWatch • Apr. 8, 2026

The name change is required because Brussels is relaxing its labelling rules, widening the legal definition of marmalade across Europe for the first time.

From BBC • Apr. 2, 2026

But Joe was readier with his definition than I had expected, and completely stopped me by arguing circularly, and answering with a fixed look, “Her.”

From "Great Expectations" by Charles Dickens

Related Words

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