c.1200, "eve of a religious festival" (an occasion for devotional watching or observance), from Anglo-French and Old French vigile "watch, guard; eve of a holy day" (12c.), from Latin vigilia "a watch, watchfulness," from vigil "watchful, awake, on the watch, alert," from PIE root *weg- (2) "be lively or active, be strong" (cognates: Old English wacan "to wake up, arise," wacian "to be awake;" Old High German wahta "watch, vigil;" see wake, v.). Meaning "watch kept on a festival eve" in English is from late 14c.; general sense of "occasion of keeping awake for some purpose" is recorded from 1711.