certified

UK: /ˈsɜːtɪˌfaɪd/ US: (sûr′tə fīd′)

From the verb certify: (⇒ conjugate)

certified is: ⓘ

v past

v past p

WordReference Random House Unabridged Dictionary of American English © 2026

cer•ti•fied  (sûr′tə fīd′), adj. 

1. having or proved by a certificate:
   a certified representative.
2. guaranteed;
   reliably endorsed:
   a certified check.
3. Law legally declared insane.
4. committed to a mental institution.

• certify + -ed² 1605–15

Collins Concise English Dictionary © HarperCollins Publishers::

certified / ˈsɜːtɪˌfaɪd/ adjective

1. holding or guaranteed by a certificate
2. endorsed or guaranteed: a certified test facility
3. (of a person) declared legally insane

WordReference Random House Learner's Dictionary of American English © 2026

cer•ti•fy /ˈsɜrtəˌfaɪ/   v., -fied, -fy•ing. 

1. 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.
2. Law to give a license to (someone), often by providing a certificate:
   [~ + object] All the teachers in our program are certified.
3. Business to guarantee (a check):
   [~ + object] The bank certified our check and I brought it back to the car dealer.
4. Law [~ + object] to declare (a person) legally insane.
5. 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.

See -cert-.

WordReference Random House Unabridged Dictionary of American English © 2026

cer•ti•fy  (sûr′tə fī′), v., -fied, -fy•ing. 
v.t. 

1. to attest as certain;
   give reliable information of;
   confirm:
   He certified the truth of his claim.
2. to testify to or vouch for in writing:
   The medical examiner will certify his findings to the court.
3. to guarantee;
   endorse reliably:
   to certify a document with an official seal.
4. Business to guarantee (a check) by writing on its face that the account against which it is drawn has sufficient funds to pay it.
5. Education to award a certificate to (a person) attesting to the completion of a course of study or the passing of a qualifying examination.
6. Law to declare legally insane and committable to a mental institution.
7. [Archaic.] to assure or inform with certainty.

v.i. 

8. 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

cer′ti•fi′er, n. 
Synonyms

• 1. corroborate, verify, validate, guarantee.

Collins Concise English Dictionary © HarperCollins Publishers::

certify / ˈsɜːtɪˌfaɪ/ verb ( -fies, -fying, -fied)

1. to confirm or attest (to), usually in writing
2. (transitive) to endorse or guarantee (that certain required standards have been met)
3. to give reliable information or assurances: he certified that it was the accused's handwriting
4. (transitive) to declare legally insane

Etymology: 14th Century: from Old French certifier, from Medieval Latin certificāre to make certain, from Latin certus certain + facere to make