- to confirm or attest (to), usually in writing
- (transitive) to endorse or guarantee (that certain required standards have been met)
- to give reliable information or assurances: he certified that it was the accused's handwriting
- (transitive) informal to declare legally insane
WordReference Random House Learner's Dictionary of American English © 2026
cer•ti•fy /ˈsɜrtəˌfaɪ/USA pronunciation
v., -fied, -fy•ing.
WordReference Random House Unabridged Dictionary of American English © 2026- to declare that something is certain or true;
confirm: [~ + object]As an expert witness he was able to certify the truth of her claim.[~ + (that) clause]was able to certify that this was the murder weapon. - Law to give a license to (someone), often by providing a certificate:[~ + object]All the teachers in our program are certified.
- Business to guarantee (a check):[~ + object]The bank certified our check and I brought it back to the car dealer.
- Law[~ + object] to declare (a person) legally insane.
- to tell or inform someone with certainty;
assure someone:[~ + (that) clause]I can certify that she is one of the best teachers I have seen.
cer•ti•fy
(sûr′tə fī′),USA pronunciation v., -fied, -fy•ing.
v.t.
v.i.
cer′ti•fi′er, n.
v.t.
- to attest as certain;
give reliable information of;
confirm:He certified the truth of his claim. - 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. - Businessto guarantee (a check) by writing on its face that the account against which it is drawn has sufficient funds to pay it.
- Educationto award a certificate to (a person) attesting to the completion of a course of study or the passing of a qualifying examination.
- Lawto declare legally insane and committable to a mental institution.
- [Archaic.]to assure or inform with certainty.
v.i.
- to give assurance;
testify;
vouch for the validity of something (usually fol. by to).
- Late Latin certificāre, equivalent. to Latin certi- (combining form of certus decided; see certain) + -ficāre -fy
- Middle French certifier
- Middle English certifien 1300–50
- 1. corroborate, verify, validate, guarantee.
Collins Concise English Dictionary © HarperCollins Publishers::
certify /ˈsɜːtɪˌfaɪ/ vb ( -fies, -fying, -fied)
'certify' also found in these entries (note: many are not synonyms or translations):
accredit
- audit
- certificate
- notaire
- notary public
- attest
- cert.
- certifiable
- certified
- decertify
- notarize
- overcertify
- qualify
- vouch