proof (n.)

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.).

1834, "to test," from proof (n.). From 1950 as short for proof-read (v.). Related: Proofed; proofing.