c. 1200, professioun, "vows taken upon entering a religious order," from Old French profession (12c.) and directly from Latin professionem (nominative professio) "public declaration," noun of action from past-participle stem of profiteri "declare openly" (see profess).

The meaning "any solemn declaration" is from mid-14c. Meaning "occupation one professes to be skilled in, a calling" is from early 15c.; meaning "body of persons engaged in some occupation" is from 1610; as a euphemism for "prostitution" (compare oldest profession) it is recorded from 1888.

Formerly theology, law, and medicine were specifically known as the professions; but, as the applications of science and learning are extended to other departments of affairs, other vocations also receive the name. The word implies professed attainments in special knowledge, as distinguished from mere skill; a practical dealing with affairs, as distinguished from mere study or investigation; and an application of such knowledge to uses for others as a vocation, as distinguished from its pursuit for one's own purposes. In professions strictly so called a preliminary examination as to qualifications is usually demanded by law or usage, and a license or other official authority founded thereon required. [Century Dictionary]

mid-15c., profeshinalle, in reference to the profession of religious orders; see profession. By 1747 of careers, "pertaining to or appropriate to a profession or calling" (especially of the skilled or learned trades from c. 1793);  In sports and amusements, "undertaken or engaged in for money" (opposed to amateur), by 1846. Related: Professionally.

early 14c., professen, "to take a vow" (in a religious order), a back-formation from profession or else from Medieval Latin professare, from professus "avowed," literally "having declared publicly," past participle of Latin profiteri "declare openly, testify voluntarily, acknowledge, make public statement of," from pro- "forth" (from PIE root *per- (1) "forward") + fateri (past participle fassus) "acknowledge, confess" (akin to fari "to speak," from PIE root *bha- (2) "to speak, tell, say").

The meaning "declare openly" is recorded from 1520s, "a direct borrowing of the sense from Latin" [Barnhart]. Related: Professed; professing.

*bhā-; Proto-Indo-European root meaning "to speak, tell, say."

It forms all or part of: abandon; affable; anthem; antiphon; aphasia; aphonia; aphonic; apophasis; apophatic; ban (n.1) "proclamation or edict;" ban (v.); banal; bandit; banish; banlieue; banns (n.); bifarious; blame; blaspheme; blasphemy; boon (n.); cacophony; confess; contraband; defame; dysphemism; euphemism; euphony; fable; fabulous; fado; fairy; fame; famous; fandango; fatal; fate; fateful; fatuous; fay; gramophone; heterophemy; homophone; ineffable; infamous; infamy; infant; infantile; infantry; mauvais; megaphone; microphone; monophonic; nefandous; nefarious; phatic; -phone; phone (n.2) "elementary sound of a spoken language;" phoneme; phonetic; phonic; phonics; phono-; pheme; -phemia; Polyphemus; polyphony; preface; profess; profession; professional; professor; prophecy; prophet; prophetic; quadraphonic; symphony; telephone; xylophone.

It is the hypothetical source of/evidence for its existence is provided by: Greek pheme "speech, voice, utterance, a speaking, talk," phōnē "voice, sound" of a human or animal, also "tone, voice, pronunciation, speech," phanai "to speak;" Sanskrit bhanati "speaks;" Latin fari "to say," fabula "narrative, account, tale, story," fama "talk, rumor, report; reputation, public opinion; renown, reputation;" Armenian ban, bay "word, term;" Old Church Slavonic bajati "to talk, tell;" Old English boian "to boast," ben "prayer, request;" Old Irish bann "law."

"the art or profession of a dentist," 1803; see dentist + -ry.

"one whose profession is advising on matters of food and nutrition and their effect on health," 1926, from nutrition + -ist.

"one whose profession is to measure the range and power of vision," 1903; see optometry + -ist.

early 15c., "spiritual calling," from Old French vocacion "call, consecration; calling, profession" (13c.) or directly from Latin vocationem (nominative vocatio), literally "a calling, a being called" from vocatus "called," past participle of vocare "to call," which is related to vox (genitive vocis) "voice" (from PIE root *wekw- "to speak"). Sense of "one's occupation or profession" is first attested 1550s.

1733, from stone (n.) + mason. Another name for the profession was hard-hewer (15c.). Stone-cutter is from 1530s; Old English had stanwyrhta "stone-wright."

"the profession of authorship or literature," mid-13c., from plural of letter (n.); as in Latin, French. Man of letters attested from 1640s.