Online Etymology Dictionary

auteur (n.): 1962, from French, literally "author" (see author (n.)).
authentic (adj.): mid-14c., "authoritative," from Old French autentique (13c., Modern French authentique) "authentic; canonical," and directly from Medieval Latin authenticus, from Greek authentikos "original, genuine, principal," from authentes "one acting on one's own authority," from autos "self" (see auto-) + hentes "doer, being," from PIE *sene- "to accomplish, achieve." Sense of "entitled to acceptance as factual" is first recorded mid-14c.

Traditionally in modern use, authentic implies that the contents of the thing in question correspond to the facts and are not fictitious; genuine implies that the reputed author is the real one; but this is not always maintained: "The distinction which the 18th c. apologists attempted to establish between genuine and authentic ... does not agree well with the etymology of the latter word, and is not now recognized" [OED].
authenticate (v.): "verify, establish the credibility of," 1650s, from Medieval Latin authenticatus, past participle of authenticare, from authenticus (see authentic). Related: Authenticated; authenticating.
authentication (n.): 1788, noun of action from authenticate (v.).
authenticity (n.): 1760; see authentic + -ity. Earlier form was authentity (1650s).
author (n.): c. 1300, autor "father," from Old French auctor, acteor "author, originator, creator, instigator (12c., Modern French auteur), from Latin auctorem (nominative auctor) "enlarger, founder, master, leader," literally "one who causes to grow," agent noun from auctus, past participle of augere "to increase" (see augment). Meaning "one who sets forth written statements" is from late 14c. The -t- changed to -th- 16c. on mistaken assumption of Greek origin.
...[W]riting means revealing onesself 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]
author (v.): 1590s, from author (n.). Revived 1940s, chiefly U.S. Related: Authored; authoring.
authorial (adj.): 1796, from author (n.) + -al (1).
authorisation (n.): chiefly British English spelling of authorization (q.v.); for spelling, see -ize.
authorise (v.): chiefly British English spelling of authorize (q.v.); for suffix, see -ize. Related: Authorised; authorising.
authoritarian (adj.): 1862, "favoring imposed order over freedom," from authority + -an. Compare authoritative, which originally had this meaning to itself. Noun in the sense of one advocating or practicing such governance is from 1859.
authoritarianism (n.): 1883; see authoritarian + -ism. Early use mostly in communist jargon.
authoritative (adj.): c. 1600, "dictatorial" (a sense now restricted to authoritarian), from Medieval Latin authoritativus (see authority). Meaning "possessing authority" is recorded from 1650s; that of "proceeding from proper authority" is from 1809. Related: Authoritatively; authoritativeness.
authority (n.): early 13c., autorite "book or quotation that settles an argument," from Old French auctorité "authority, prestige, right, permission, dignity, gravity; the Scriptures" (12c.; Modern French autorité), from Latin auctoritatem (nominative auctoritas) "invention, advice, opinion, influence, command," from auctor "master, leader, author" (see author (n.)).

Usually spelled with a -c- in English till 16c., when it was dropped in imitation of the French. Meaning "power to enforce obedience" is from late 14c.; meaning "people in authority" is from 1610s. Authorities "those in charge, those with police powers" is recorded from mid-19c.
authorization (n.): c. 1600, from authorize + -ation. Earlier form was auctorisation (late 15c.).
authorize (v.): "give formal approval to," late 14c., autorisen, from Old French autoriser "authorize, give authority to" (12c.), from Medieval Latin auctorizare, from auctor (see author (n.)). Modern spelling from 16c. Related: Authorized; authorizing.
authorship (n.): c. 1500, "the function of being a writer," from author (n.) + -ship. Meaning "literary origin" is attested from 1825.
autism (n.): 1912, from German Autismus, coined 1912 by Swiss psychiatrist Paul Bleuler (1857-1939) from comb. form of Greek autos- "self" (see auto-) + -ismos suffix of action or of state. The notion is of "morbid self-absorption."
autistic (adj.): 1912 (Bleuler), from autism (q.v.). Noun meaning "person with autism" is recorded from 1968 (earlier in this sense was autist).
auto (n.): shortened form of automobile, 1899; same development yielded French auto.
auto-: word-forming element meaning "self, one's own, by oneself," from Greek auto- "self, one's own," combining form of autos "self, same," which is of unknown origin. Before a vowel, aut-; before an aspirate, auth-. In Greek also used as a prefix to proper names, as in automelinna "Melinna herself." The opposite prefix would be allo-.
auto-da-fe (n.): 1723, "sentence passed by the Inquisition" (plural autos-da-fé), from Portuguese auto-da-fé "judicial sentence, act of the faith," especially the public burning of a heretic, from Latin actus de fide, literally "act of faith." Although the Spanish Inquisition is better-known today, there also was one in Portugal.
auto-erotic (adj.): 1898, coined by Havelock Ellis from auto- + erotic. Related: Auto-eroticism.
autobahn (n.): 1937, German, from auto "motor car, automobile" + bahn "path, road," from Middle High German ban, bane "way, road," literally "strike" (as a swath cut through), from PIE *gwhen- "to strike, kill" (see bane).
autobiography (n.): 1797, from auto- + biography. Related: Autobiographical.
autocade (n.): 1922, from auto(mobile) + ending from cavalcade.
autocar (n.): 1895, from auto- + car.
Which is it to be? We observe that the London Times has lent the weight of its authority to the word "autocar," which it now prints without the significant inverted commas but with a hyphen, "auto-car." We believe that the vocable originated with a journal called the Hardwareman, which succeeded in obtaining the powerful support of the Engineer for its offspring. As for ourselves, being linguistic purists, we do not care for hybrid constructions--"auto" is Greek, while "car" is Latin and Celtic. At the same time, such clumsy phrases as "horseless carriages," "mechanical road carriages," and "self-propelled vehicles" are not meeting with general favour. Why not therefore adopt the philogically sound "motor-car," which could be run into a single word, "motorcar"? ["The Electrical Engineer," Dec. 20, 1895]
autochthon (n.): 1640s, "one sprung from the soil he inhabits" (plural autochthones), from Greek autokhthon "aborigines, natives," literally "sprung from the land itself," used of the Athenians and others who claimed descent from the Pelasgians, from auto- "self" (see auto-) + khthon "land, earth, soil" (see chthonic).
autochthonic (adj.): 1827, from autochthon + -ic.
autochthonous (adj.): "native, indigenous," 1845, from autochthon + -ous.
autoclave (n.): 1880, from French, literally "self-locking," from auto- "self" (see auto-) + Latin clavis "key" (see slot (n.2)).
autocracy (n.): 1650s, "independent power, self-sustained power," from French autocratie, from Greek autokrateia "ruling by oneself," noun of state from autokrates (see autocrat). Meaning "absolute government, supreme political power" is recorded from 1855.
autocrat (n.): 1803, from French autocrate, from Greek autokrates "ruling by oneself, absolute, autocratic," from autos- "self" (see auto-) + kratia "rule," from kratos "strength, power" (see -cracy). First used by Robert Southey, with reference to Napoleon. An earlier form was autocrator (1789), used in reference to the Russian Czars. Earliest form in English is the fem. autocratress (1762).
autocratic (adj.): 1823, from French autocratique, from autocrate, from Greek autokrates (see autocrat). Earlier autocratoric (1670s) was directly from Greek autokratorikos. Autocratical is attested from 1801.
autodidact (n.): 1746, from Greek autodidaktos "self-taught" (see autodidactic).
autodidactic (adj.): "self-taught," 1838, from Greek autodidaktikos "self-taught," from autos "self" (see auto-) + didaktos "taught" (see didactic).
autogenous (adj.): "self-generated," 1846, earlier autogeneal (1650s), from Greek autogenes "self-produced," from autos "self" (see auto-) + genes "formation, creation" (see genus). Modern form and biological use of the word said to have been coined by English paleontologist Richard Owen (1804-1892).
autograph (n.): "a person's signature," 1791, from Latin autographum, from Greek autographon, neuter of autographos "written with one's own hand," from autos- "self" (see auto-) + graphein "to write" (originally "to scratch;" see -graphy). Used earlier (1640s) to mean "author's own manuscript."
autograph (v.): "to sign one's name," 1837, from autograph (n.). Related: Autographed; autographing. Earlier "to write with one's own hand" (1818).
autoharp (n.): 1882, name on a patent taken out by Charles F. Zimmermann of Philadelphia, U.S.A., for an improved type of harp, an instrument considerably different from the modern autoharp, actually a chord zither, which was invented about the same time by K.A. Gütter of Markneukirchen, Germany, who called it a Volkszither.
autoimmune (adj.): 1952, from auto- + immune.
autolatry (n.): "self-worship," 1620s (in Latinate form autolatria), from auto- + -latry.
automaker (n.): "manufacturer of automobiles," 1925, from auto + maker.
automat (n.): "automated cafeteria," 1903, probably from automatic.
automate (v.): "to convert to automatic operation," 1954, back-formation from automated (q.v.). Ancient Greek verb automatizein meant "to act of oneself, to act unadvisedly." Related: Automating.
automated (adj.): 1952, American English, adjective based on automation.
automatic (adj.): "self-acting, moving or acting on its own," 1812, from Greek automatos, used of the gates of Olympus and the tripods of Hephaestus (also "without apparent cause, by accident"), from autos "self" (see auto-) + matos "thinking, animated" (see automaton). Of involuntary animal or human actions, from 1748, first used in this sense by English physician and philosopher David Hartley (1705-1757). In reference to a type of firearm, from 1877; specifically of machinery that imitates human-directed action from 1940.
automatic (n.): "automatic weapon," 1902, from automatic (adj.). Meaning "motorized vehicle with automatic transmission" is from 1949.
automatically (adv.): 1834, "involuntarily, unconsciously;" see automatic + -ly (2).
automation (n.): 1948, in the manufacturing sense, coined by Ford Motor Co. Vice President Delmar S. Harder, from automatic + -ion. Earlier (1838) was automatism, which meant "quality of being automatic" in the classical sense.