In Middle English, -u- and -v- were used interchangeably, though with a preference for v- as the initial letter (vnder, vain, etc.) and -u- elsewhere (full, euer, etc.). The distinction into consonant and vowel identities was established in English by 1630, under influence of continental printers, but into 19c. some dictionaries and other catalogues continued to list -u- and -v- words as a single series.
No native Anglo-Saxon words begin in v- except those (vane, vat, vixen) altered by the southwestern England habit of replacing initial f- with v- (and initial s- with z-). Confusion of -v- and -w- also was a characteristic of 16c. Cockney accents.
As a Roman numeral, "five." In German rocket weapons systems of World War II, it stood for Vergeltungswaffe "reprisal weapon." V-eight as a type of motor engine is recorded from 1929 (V-engine is attested from 1909), so called for the arrangement. The V for "victory" hand sign was conceived January 1941 by Belgian politician and resistance leader Victor de Laveleye, to signify French victoire and Flemish vrijheid ("freedom"). It was broadcast into Europe by Radio België/Radio Belgique and popularized by the BBC by June 1941, from which time it became a universal allied gesture.