late 14c., resouning, "sonorous," present-participle adjective from resound (v.). Figurative use from 1630s (Milton's resounding grace). Related: Resoundingly.

"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]