late 14c., "an overseer, guardian, steward," from Latin actor "an agent or doer; a driver (of sheep, etc.)," in law, "accuser, plaintiff," also "theatrical player, orator," from past-participle stem of agere "to set in motion, drive, drive forward," hence "to do, perform," also "act on stage, play the part of; plead a cause at law" (from PIE root *ag- "to drive, draw out or forth, move"). In English from mid-15c. as "a doer, maker," also "a plaintiff at law." The sense of "one who performs in plays" is by 1580s, originally applied to both men and women. Related: Actorish; actorly; actory.
mid-14c., auctor, autour, autor "father, creator, one who brings about, one who makes or creates" someone or something, from Old French auctor, acteor "author, originator, creator, instigator" (12c., Modern French auteur) and directly from Latin auctor "promoter, producer, father, progenitor; builder, founder; trustworthy writer, authority; historian; performer, doer; responsible person, teacher," literally "one who causes to grow," agent noun from auctus, past participle of augere "to increase" (from PIE root *aug- (1) "to increase").
From late 14c. as "a writer, one who sets forth written statements, original composer of a writing" (as distinguished from a compiler, translator, copyist, etc.). Also from late 14c. as "source of authoritative information or opinion," which is now archaic but is the sense behind authority, etc.
In Middle English the word sometimes was confused with actor. The -t- changed to -th- 16c., on the model of a change in Medieval Latin which was made on the mistaken assumption of a Greek origin and from confusion with authentic.
...[W]riting means revealing oneself to excess .... This is why one can never be alone enough when one writes, why even night is not night enough. ... I have often thought that the best mode of life for me would be to sit in the innermost room of a spacious locked cellar with my writing things and a lamp. Food would be brought and always put down far away from my room, outside the cellar's outermost door. The walk to my food, in my dressing gown, through the vaulted cellars, would be my only exercise. I would then return to my table, eat slowly and with deliberation, then start writing again at once. And how I would write! From what depths I would drag it up! [Franz Kafka, "Letters to Felice," 1913]
Proto-Indo-European root meaning "to drive, draw out or forth, move."
It forms all or part of: act; action; active; actor; actual; actuary; actuate; agency; agenda; agent; agile; agitation; agony; ambagious; ambassador; ambiguous; anagogical; antagonize; apagoge; assay; Auriga; auto-da-fe; axiom; cache; castigate; coagulate; cogent; cogitation; counteract; demagogue; embassy; epact; essay; exact; exacta; examine; exigency; exiguous; fumigation; glucagon; hypnagogic; interact; intransigent; isagoge; litigate; litigation; mitigate; mystagogue; navigate; objurgate; pedagogue; plutogogue; prodigal; protagonist; purge; react; redact; retroactive; squat; strategy; synagogue; transact; transaction; variegate.
It is the hypothetical source of/evidence for its existence is provided by: Greek agein "to lead, guide, drive, carry off," agon "assembly, contest in the games," agōgos "leader," axios "worth, worthy, weighing as much;" Sanskrit ajati "drives," ajirah "moving, active;" Latin actus "a doing; a driving, impulse, a setting in motion; a part in a play;" agere "to set in motion, drive, drive forward," hence "to do, perform," agilis "nimble, quick;" Old Norse aka "to drive;" Middle Irish ag "battle."
1764, "comic actor in an opera," from Italian buffo "a comic actor," from buffare "to mock; to puff" (see buffoon).
as a generic name or designation for a great actor, 1640s, from Quintus Roscius Gallus (d. 62 B.C.E.), the celebrated Roman actor. Since 19c., mostly (if at all), historical and in reference to David Garrick.
1580s, "comic poet," later (c. 1600) "actor in stage comedies," also, generally, "actor;" from French comédien, from comédie (see comedy). Meaning "professional joke-teller, entertainer who performs to make the audience laugh" is from 1898. Old English had heahtorsmið "laughter-maker."