certify
Americanverb (used with object)
-
certifies,
present (3rd person singular)
-
certified,
past participle, past
-
certifying
present participle
-
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)
-
certifies,
present (3rd person singular)
-
certified,
past participle, past
-
certifying
present participle
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
-
(tr) (of a bank) to state in writing on (a cheque) that payment is guaranteed
Other Word Forms
Derived Forms
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certifiernoun
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precertifyverb (used with object)
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recertifyverb (used with object)
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uncertifyingadjective
Inflected Forms
Participles
Conjugated Forms
Present
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certifysimple
-
certifiessimple
-
have certifiedperfect
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has certifiedperfect
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am certifyingprogressive
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are certifyingprogressive
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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.
See Examples For:
People can now certify their expertise with particular AI platforms and strategies through paid and free certification programs.
From MarketWatch ● Jul. 31, 2026
Federal regulators are expected to certify Boeing’s BA -0.82%decrease; down pointing triangle second-to-last version of its 737 later this month, marking a significant—albeit belated—milestone for the plane maker.
From The Wall Street Journal ● Jul. 9, 2026
County elections officials must report their final results by July 3, giving state officials a week to certify all election results.
From Los Angeles Times ● Jun. 27, 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
Now he has a degree to certify his nosiness.
From "On the Come Up" by Angie Thomas
August 3: The FAA certifies the 737 MAX 7, Boeing's first new aircraft since the 2018 and 2019 crashes.
From Barron's ● Aug. 3, 2026
Raffensperger, whose office oversees Georgia's elections and certifies results, confirmed that Biden won the state even after multiple reviews.
From BBC ● Dec. 12, 2025
Despite eventually allowing protestors to voice their opposition to the Dodger Stadium gondola project, Metro certifies a revised environmental impact report.
From Los Angeles Times ● Dec. 8, 2025
This budget enacts a “deemed approved” permitting process—which automatically certifies pending permits after an established time frame—for Department of Environmental Protection regulations.
From The Wall Street Journal ● Nov. 21, 2025
Washington in a letter certifies to his "great share in preventing worse extremities" and thanks him for his exertions.
From Great Men and Famous Women. Vol. 2 A series of pen and pencil sketches of the lives of more than 200 of the most prominent personages in History by Charles F. (Charles Francis) Horne
So before you start, speak to a certified exercise physiologist or physiotherapist.
From Science Daily ● Aug. 16, 2026
The App Drivers Union was certified in May to represent roughly 70,000 Uber and Lyft drivers in that state.
From Los Angeles Times ● Aug. 15, 2026
Consult with a certified financial planner and a tax accountant.
From MarketWatch ● Aug. 14, 2026
The safest way is to use certified solar glasses or create a pinhole viewer.
From BBC ● Aug. 11, 2026
And to an audience stilled with awe, he distributed certified photostatic copies of the obscure regulation on which he had uilt his unforgettable triumph.
From "Catch-22" by Joseph Heller
EAC also oversees the federal testing and certification program for voting systems, accrediting labs and certifying whether machines meet federal standards known as the Voluntary Voting System Guidelines.
From Salon ● Jul. 11, 2026
The third-party certifying body administers random testing throughout the growing process and tests each product that arrives at the company’s New Jersey warehouse before it is released to stores, according to the website.
From Los Angeles Times ● May 12, 2026
The certifying official notes that the filer “will be in compliance” only “once the filer divests these assets.”
From MarketWatch ● May 7, 2026
Mr. Bessent’s prescription is a mix of targeted regulation—controlling advanced chip exports, certifying systems in a manner akin to aircraft safety—and a lighter touch that avoids stifling innovation.
From The Wall Street Journal ● Apr. 24, 2026
The monks who ran the school were very particular about tests and qualifications, and it was time to try the certifying exam again.
From "The Gene" by Siddhartha Mukherjee
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.
