autopilot n.

word-forming element meaning "self, one's own, by oneself, of oneself" (and especially, from 1895, "automobile"), from Greek autos, reflexive pronoun, "self, same," which is of unknown origin. It also was a common word-forming element in ancient Greek, as in modern English, but very few of the old words have survived the interval. In Greek, as a word-forming element, auto- had the sense of "self, one's own, of oneself ('independently'); of itself ('natural, native, not made'); just exactly; together with." Before a vowel, it became aut-; before an aspirate, auth-. In Greek it also was used as a prefix to proper names, as in automelinna "Melinna herself." The opposite prefix would be allo-.

1510s, "one who steers a ship," especially one who has charge of the helm when the ship is passing in or out of harbor, from French pillote (16c.), from Italian piloto, supposed to be an alteration of Old Italian pedoto, which usually is said to be from Medieval Greek *pedotes "rudder, helmsman," from Greek pedon "steering oar," related to pous (genitive podos) "foot," from PIE root *ped- "foot." The change of -d- to -l- in Latin-derived languages ("Sabine -l-") parallels that in odor/olfactory; see lachrymose.

The transferred or figurative sense "a guide, a director of the course of others" is by 1590s. The literal sense was extended by 1848 to "one who controls a balloon," and by 1907 to "one who flies an airplane."

As an adjective, 1788 as "pertaining to a pilot;" from 1928 as "serving as a prototype," thus the noun pilot meaning "pilot episode" (etc.), attested from 1962. A pilot light (by 1890) is a very small light kept burning beside a large burner to automatically light the main burner when the flow is turned on.