early 15c., "action of certifying," from French certificat, from Medieval Latin certificatum "thing certified," noun use of neuter past participle of certificare "to make certain" (see certify). Of documents of certification, testifying to the truth of the facts stated, from mid-15c.; especially a signed document attesting to someone's authorization to practice or do stated things (1540s).
"licensed or authorized by certificate," 1610s, past-participle adjective from obsolete certificate (v.) "furnish (someone) with a certificate," from Medieval Latin certificatus, past participle of certificare "to make certain" (see certify).
"attested by certificate," 1610s, past-participle adjective from certify. Certified public accountant attested from 1896; certified mail from 1955.
1979 as an abbreviation of compact disc as a digital system of information storage. By 1959 as an abbreviation of certificate of deposit "written statement from a bank acknowledging it has received a sum of money from the person named" (1819).
early 15c., "notification;" mid-15c., "demonstration, proof," from Medieval Latin certificationem (nominative certificatio), noun of action from past-participle stem of Late Latin certificare "to make certain" (see certify). Meaning "act of providing with a legal certificate" is from 1881.
Used from mid-17c. especially in law, and there via its appearance at the head of legal document involving seizure, deposition, etc. ("Certificate of caption"), the sense was extended to "the beginning of any document," and thence to "heading of a chapter or section of an article" (1789), and, especially in U.S., "description or title below an illustration" (1919).
c. 1400, ordinarie, "regular, customary, belonging to the usual order or course, conformed to a regulated sequence or arrangement," from Old French ordinarie "ordinary, usual" and directly from Latin ordinarius "customary, regular, usual, orderly," from ordo (genitive ordinis) "row, rank, series, arrangement" (see order (n.)).
From 1580s as "common in occurrence, not distinguished in any way." Its various noun uses, dating to late 14c. and common until 19c., are now largely extinct except in out of the ordinary (1893) in which the sense of ordinary is "established or due sequence; something regular or customary." In British education, Ordinary level (abbrev. O level), "lowest of the three levels of General Certificate of Education," is attested from 1947. Related: Ordinarily.