vigil [ME] Vigil comes from Latin vigilia ‘wakefulness’, from vigil ‘awake’. It was first used for the night before a religious festival, when people might stay wakeful all night in prayer. Related words include vigilant [LME]; vigilance [L16th]; and vigilante [M19th] adopted from a Spanish word with the literal meaning ‘vigilant’. Surveillance [E19th] is from the same root and is literally watching over something, also found when someone invigilates [M16th] an exam.