wakefulness maintained for any reason during the normal hours for sleeping.

a watch or a period of watchful attention maintained at night or at other times

The nurse kept her vigil at the bedside of the dying man.

a period of wakefulness from inability to sleep.

Ecclesiastical .

a devotional watching, or keeping awake, during the customary hours of sleep.

Sometimes, vigils. a nocturnal devotional exercise or service, esp. on the eve before a church festival.

the eve, or day and night, before a church festival, esp. an eve that is a fast.

noun

attention , awareness , duty , eagle eye * , guard , lookout , monitoring , nightwatch , notice , observance , observation , patrol , stake-out , surveillance , vigilance , watchfulness , watch , prayers , service , wake