c. 1200, preove "evidence and argumentation to establish the fact of (something) beyond reasonable doubt," from Anglo-French prove, preove, Old French proeve, prueve "proof, test, experience" (13c., Modern French preuve), from Late Latin proba "a proof," a back-formation from Latin probare "to prove" (see prove). "The devocalization of v to f ensued upon the loss of final e; cf. the relation of v and f in believe, belief, relieve, relief, behove, behoof, etc." [OED, 2nd ed., 1989].

The meaning "act of proving" is early 14c. The meaning "act of testing or making trial of anything" is from late 14c., from influence of prove. The meaning "standard of strength of distilled liquor" is from 1705, on the notion of "having been tested as to degree of strength." The use in photography is from 1855. The typographical sense of "trial impression to test type" is from c. 1600. The numismatic sense of "coin struck to test a die" is from 1762; now mostly in reference to coins struck from highly polished dies, mainly for collectors.

The adjectival sense "impenetrable, able to resist" (as in proof against) is recorded from 1590s, from the noun in expressions such as proof of (mid-15c.), hence the extended senses involving "of tested power against" in compounds such as storm-proof (1590s), fireproof (1630s), rust-proof (1690s), bomb-proof (1702), waterproof (1725), fool-proof (1902), Milton's branching elm star-proof. A Donne sermon from 1631 has temptation-proof.

In later use often in advertisers' coinages, such as spill-proof, attested from 1909 in reference to carpet sweepers, by 1920 also in newspaper ads for garbage cans, clothes for boys, a dairy pail a cow can't kick over, etc. (It was used by 1902 of a wagon that won't upset.) Also child-proof (1933). Shakespeare has shame-proof.

The expression the proof is in the pudding (1915) is a curious perversion of earlier proof of the pudding shall be in the eating (1708), with proof in the sense "quality of proving good or turning out well" (17c.).

"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, originally 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]