vig·il 
(vĭjəl)
(vĭjəl)n.
1.
a. A watch kept during normal sleeping hours.
b. The act or a period of observing; surveillance.
2. The eve of a religious festival observed by staying awake as a devotional exercise.
3. often vigils Ritual devotions observed on the eve of a holy day.
4. A public assembly convened, often at night, as a political protest or in support of a cause.
[Middle English vigile, a devotional watching, from Old French, from Latin vigilia, wakefulness, watch, from vigil, awake; see weg- in the Appendix of Indo-European roots.]