certify
Americanverb (used with object)
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to attest as certain; give reliable information of; confirm.
He certified the truth of his claim.
- Synonyms:
- guarantee, validate, verify, corroborate
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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.
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to guarantee (a check) by writing on its face that the account against which it is drawn has sufficient funds to pay it.
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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)
-
to give assurance; testify; vouch for the validity of something (usually followed byto ).
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)
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to give reliable information or assurances
he certified that it was Walter's handwriting
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(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
- certifier noun
- precertify verb (used with object)
- recertify verb (used with object)
- uncertifying adjective
Etymology
Origin of certify
1300–50; Middle English certifien < Middle French certifier < Late Latin certificāre, equivalent to Latin certi- (combining form of certus decided; certain ) + -ficāre -fy
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.
Boeing is working to certify the widebody jet for commercial service.
From Barron's • Feb. 19, 2026
Instead of going through the usual regulatory process, residents using federal emergency funds to rebuild would have to certify compliance with local standards.
From Los Angeles Times • Feb. 3, 2026
The government also alleged the couple drew around $2 million in a kickback scheme related to a state supplier of personal protective equipment during the Covid-19 pandemic that Sun helped certify.
From The Wall Street Journal • Dec. 22, 2025
However, BBC News also found British companies selling dried seahorses, which can only be traded in the UK if the seller can certify they were sustainably harvested.
From BBC • Dec. 11, 2025
“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
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.