Certified

having or proved by a certificate:
a certified representative.
guaranteed; reliably endorsed:
a certified check.
legally declared insane.
committed to a mental institution.
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.
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.
to declare legally insane and committable to a mental institution.
Archaic. to assure or inform with certainty.
to give assurance; testify; vouch for the validity of something (usually followed by to).
adjective
holding or guaranteed by a certificate
endorsed or guaranteed: a certified cheque
(of a person) declared legally insane
verb -fies, -fying, -fied
to confirm or attest (to), usually in writing: the letter certified her age
(transitive) 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
(transitive) to declare legally insane
(transitive) (US & Canadian) (of a bank) to state in writing on (a cheque) that payment is guaranteed
v.

mid-14c., “to declare the truth of,” also “to vouch for or confirm” (an official record, etc.), from Old French certefiier “make certain, witness the truth of” (12c.), from Late Latin certificare “to certify, to make certain,” from Latin certus (see certain) + root of facere “to make, do” (see factitious). Also used in Middle English in broader senses of “inform, give notice; instruct, to direct; to designate.” Related: Certified; certifying. Certified public accountant attested from 1896.