certify
Americanverb (used with object)
-
to attest as certain; give reliable information of; confirm.
He certified the truth of his claim.
- Synonyms:
- guarantee, validate, verify, corroborate
-
to testify to or vouch for in writing.
The medical examiner will certify his findings to the court.
-
to guarantee; endorse reliably.
to certify a document with an official seal.
-
to guarantee (a check) by writing on its face that the account against which it is drawn has sufficient funds to pay it.
-
to award a certificate to (a person) attesting to the completion of a course of study or the passing of a qualifying examination.
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to declare legally insane and committable to a mental institution.
-
Archaic. to assure or inform with certainty.
verb (used without object)
verb
-
to confirm or attest (to), usually in writing
the letter certified her age
-
(tr) to endorse or guarantee (that certain required standards have been met)
-
to give reliable information or assurances
he certified that it was Walter's handwriting
-
(tr) to declare legally insane
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(tr) (of a bank) to state in writing on (a cheque) that payment is guaranteed
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
-
certifysimple
-
certifiessimple
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have certifiedperfect
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has certifiedperfect
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am certifyingprogressive
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are certifyingprogressive
-
is certifyingprogressive
-
have been certifyingperfect progressive
-
has been certifyingperfect progressive
Past
-
certifiedsimple
-
had certifiedperfect
-
was certifyingprogressive
-
were certifyingprogressive
-
had been certifyingperfect progressive
Future
Etymology
Origin of certify
1300–50; Middle English certifien < Middle French certifier < Late Latin certificāre, equivalent to Latin certi- (combining form of certus decided; see certain) + -ficāre -fy
Explanation
To certify is to provide proof for something or to license someone, like a lawyer. You can certify a lawyer or certify that someone’s insane. Either way, when you certify something, you make it official. To certify is to have evidence that something is true, to make certain. If you certify that you own a house, you prove it's yours. Vouching for a friend can certify that the friend is a good person. Professionals like lawyers, doctors, and accountants must be certified. Being certified assures others that the person is qualified. Certify also refers to declaring someone legally insane, so make sure your doctor is certified by the medical board, not the loony bin.
Vocabulary lists containing certify
Stargirl
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The Dawes Act
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This Week In Words: November 28–December 4, 2020
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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.
The California secretary of state is expected to officially certify the measure for the Nov. 3 ballot on Thursday evening.
From Los Angeles Times • Jun. 26, 2026
If that doesn’t happen, the secretary of state will certify the initiative on that date as qualified for the ballot.
From The Wall Street Journal • Jun. 18, 2026
Counties can ask for an extension, and they still have up to 30 days to certify the results, so the law only goes so far.
From Salon • Jun. 9, 2026
Final results must be reported to the California Secretary of State by 3 July and the secretary will certify results on 10 July 2026.
From BBC • Jun. 4, 2026
“Well, then, it’s up to me to certify you, isn’t it?”
From "Challenger Deep" by Neal Shusterman
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.
