define

American  

[dih-fahyn] / dɪˈfaɪn /

verb (used with object)

defined, defining

1. to state or set forth the meaning of (a word, phrase, etc.).

   They disagreed on how to define “liberal.”

2. to explain or identify the nature or essential qualities of; describe.

   to define judicial functions.

3. to fix or lay down clearly and definitely; specify distinctly.

   to define one's responsibilities.

   Synonyms:

   enumerate, detail, describe, name, state

4. to determine or fix the boundaries or extent of.

   to define property with stakes.

5. to make clear the outline or form of.

   The roof was boldly defined against the sky.

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verb (used without object)

defined, defining

1. to set forth the meaning of a word, phrase, etc.; construct a definition.

define British  

/ dɪˈfaɪn /

verb

1. to state precisely the meaning of (words, terms, etc)

2. to describe the nature, properties, or essential qualities of

3. to determine the boundary or extent of

4. (often passive) to delineate the form or outline of

   the shape of the tree was clearly defined by the light behind it

5. to fix with precision; specify

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Other Word Forms

• definability noun
• definable adjective
• definably adverb
• definement noun
• definer noun
• misdefine verb (used with object)
• nondefinability noun
• nondefinable adjective
• nondefinably adverb
• nondefined adjective
• nondefiner noun
• predefine verb (used with object)
• redefine verb (used with object)
• self-defined adjective
• semidefined adjective
• undefinable adjective

Etymology

Origin of define

First recorded in 1325–75; Middle English def(f)inen, from Anglo-French, Old French definer “to put an end to,” from Latin dēfīnīre ”to limit, define,“ equivalent to dē- “from, away from, out of” + fīnīre “to end”; see origin at de-, finish

Explanation

If you can't define a word, turn to the dictionary. That's always the best way to learn the definition. Likewise, anything you can describe completely is something you can define. The early French and Latin roots of the verb mean something closer to "to limit" or "to create a boundary," but this is really what we do when we define something: we limit its meaning to something specific. So when you're thinking about the word define, remember that you're looking to create a boundary of meaning around it, whether you're specifying the meaning of a word or a larger concept. To define a word such as astronomy is to define both the word and the realm of science that it's concerned with.

Example Sentences

"How you define having a full life, a satisfying life and a meaningful one is very personal," Oscar, Bafta and Golden Globe winner Hathaway says.

From BBC • May 1, 2026

"Investors will be watching for clues about how Ternus plans to balance Apple's cautious AI posture with the pressure to define the next consumer device for the AI era."

From Barron's • Apr. 30, 2026

Some of the people who depend on that system most are among the least represented in the decisions that define it.

From Los Angeles Times • Apr. 28, 2026

The Ramones had a deal with Sire by late 1975, and the quartet went on to define punk’s stagecraft and minimalist garage-band sound.

From The Wall Street Journal • Apr. 27, 2026

“You don’t get to define us,” the mystery girl said calmly.

From "The School for Whatnots" by Margaret Peterson Haddix

Related Words

• characterize
• construe
• decide
• delineate
• describe
• designate
• detail
• determine
• exemplify
• explain
• illustrate
• interpret
• prescribe
• represent
• specify
• spell out