define
Americanverb (used with object)
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to state or set forth the meaning of (a word, phrase, etc.).
They disagreed on how to define “liberal.”
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to explain or identify the nature or essential qualities of; describe.
to define judicial functions.
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to fix or lay down clearly and definitely; specify distinctly.
to define one's responsibilities.
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to determine or fix the boundaries or extent of.
to define property with stakes.
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to make clear the outline or form of.
The roof was boldly defined against the sky.
verb (used without object)
verb
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to state precisely the meaning of (words, terms, etc)
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to describe the nature, properties, or essential qualities of
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to determine the boundary or extent of
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(often passive) to delineate the form or outline of
the shape of the tree was clearly defined by the light behind it
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to fix with precision; specify
Other Word Forms
Derived Forms
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definabilitynoun
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misdefineverb (used with object)
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nondefinablyadverb
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predefineverb (used with object)
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definableadjective
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nondefinabilitynoun
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undefinableadjective
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self-definedadjective
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redefineverb (used with object)
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definernoun
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definablyadverb
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nondefinedadjective
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semidefinedadjective
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definementnoun
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nondefinableadjective
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nondefinernoun
Conjugated Forms
Present
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have definedperfect
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has definedperfect 3rd person singular
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have been definingperfect progressive
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am definingprogressive 1st person singular
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definessingular 3rd person
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is definingprogressive 3rd person singular
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definingparticiple
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has been definingperfect progressive 3rd person singular
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are definingprogressive
Past
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had definedperfect
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had been definingperfect progressive
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was definingprogressive singular
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were definingprogressive plural
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definedparticiple
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definedsimple
Future
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.
Vocabulary lists containing define
The Language of Standardized Tests, List 1
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Jim Burke's Academic Vocabulary List
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The ACT: The Language of the Test, List 1
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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.
His run of hits, including “The Dance,” “Friends in Low Places” and “Shameless,” helped define the sound of country radio for years.
From The Wall Street Journal • Jun. 3, 2026
To secure the extraordinary unrealized profits that define so many portfolios, investors could consider our preferred hedging strategy: ratio spreads.
From Barron's • Jun. 3, 2026
For Hughes, whose contract expires next summer, Iraola's appointment could define his tenure at Liverpool.
From BBC • Jun. 1, 2026
The service that launched CBS and helped define the broadcast industry had its final newscast Friday.
From Los Angeles Times • Jun. 1, 2026
This moment would define my memory of that night, and of the many nights like it, for a decade.
From "Educated" by Tara Westover
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.