c.1400, in phrase in a twynk of oon eye "suddenly, almost instantaneously," from twink (v.) "to wink," probably from Old English twincan (see twinkle, v.). Meaning "a twinkle" is from 1830. Meaning "young sexually attractive person" is recorded from 1963, probably from Twinkie; but compare 1920s-30s British homosexual slang twank in a similar sense.