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
-
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
When a manufacturer applies to certify a charging cable, it must submit 50 samples for evaluation.
From The Wall Street Journal ● Jul. 13, 2026
Drivers in Massachusetts for ride-hailing apps such as Uber and Lyft have become the first in the nation to certify a union.
From Los Angeles Times ● Jun. 16, 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
“They will certify the results of this test before we make them public,” said Dr. Garcia.
From "The Smartest Kid in the Universe" by Chris Grabenstein
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
Denise Brown, whose Caregiving Years Training Academy certifies caregiving consultants, says Nonie’s monthlong stay demonstrated her desire to make sure her parents were all right.
From The Wall Street Journal ● Jul. 4, 2026
Among other things, it certifies animal safety on farms as well as on movie sets.
From Los Angeles Times ● May 12, 2026
Each year, the US government formally certifies whether several countries are fully co-operating with US-led counternarcotic efforts, and those which are found to be wanting risk having their US funding cut.
From BBC ● Sep. 16, 2025
The Chicago old lady in like manner, after having had Doctor Newton’s thumbs “jobbed” into her ears, certifies that she heard next morning from her son in California.
From The Humbugs of the World An Account of Humbugs, Delusions, Impositions, Quackeries, Deceits and Deceivers Generally, in All Ages by P. T. (Phineas Taylor) Barnum
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
For those wanting to watch the eclipse, the safest way to do so is by using certified eclipse glasses that meet the ISO 12312-2 safety standard, or by viewing the eclipse indirectly.
From BBC ● Aug. 11, 2026
And is 500 certified attacks really such a modest number, considering how few people go into the North American woods?
From "A Walk in the Woods" by Bill Bryson
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
Vertical Aerospace is still certifying aircraft for commercial service and isn’t as well-known as some of the other players trying to create a “low altitude economy,” including Joby Aviation, Archer Aviation, and Beta Technologies.
From Barron's ● Mar. 26, 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.
