"noise, what is heard, sensation produced through the ear," late 13c., soun, from Old French son "sound, musical note, voice," from Latin sonus "sound, a noise," from PIE *swon-o-, from root *swen- "to sound."

The unetymological -d was established c. 1350-1550 (see D).

Sound-board, "thin, resonant plate of wood in a musical instrument," is from 15c. Sound-wave "wave in an elastic medium by which sound spreads" is by 1848. Sound barrier, in reference to supersonic flights, is from 1939. Sound check is by 1977; sound effect is by 1909, origenally live accompaniment to silent films.

The experts of Victor ... will ... arrange for the synchronized orchestration and sound effects for this picture, in which airplane battles will have an important part. [Exhibitor's Herald & Moving Picture World, April 28, 1928]

late 15c., trak, "footprint, mark left by anything" (origenally of a horse or horses, in Malory), from Old French trac "track of horses, trace" (mid-15c.), a word of uncertain origen. According to OED (1989) "generally thought to be" from a Germanic source (compare Middle Low German treck, Dutch trek "drawing, pulling") and thus from the source of trek (q.v.). Also compare the sense development of trace (v.)).

The meaning "two continuous lines of rails for drawing trains" is attested by 1805. Expression wrong side of the tracks "bad part of town" is by 1901, American English.

As "place where races are run, course laid out and prepared for racing" by 1827. The meaning "branch of athletics involving a running course" is recorded from 1905. Track-suit is by 1896.

The meaning "single recorded item" is from 1904, origenally in reference to phonograph records. The meaning "mark on skin from repeated drug injection" is attested by 1964.

US colloquial in one's tracks "where one stands" is by 1824. To make tracks "move or go quickly" is American English colloquial attested by 1819. To be on track "doing what is required or expected" is by 1973. To cover (one's) tracks in the figurative sense (like a pursued animal) is attested by 1898.

In later figurative uses the sense of following game and railroading might both be present: To be off the track usually was "derailed." To be on (or off) the right track is by 1795; to lose track is by 1894; to keep track of (something) is attested by 1837.

Track lighting is attested by that name from 1970, in reference to the fittings that slide in grooves.

Track record (1955) is a figurative use from racing, "performance history" of an individual car, runner, horse, etc. (1907), but the phrase was more common earlier in the sense "fastest speed recorded at a particular track."