vigil

Short definition from Wiktionary

Noun

1. 1
   An instance of keeping awake during normal sleeping hours, especially to keep watch or pray.
2. 2
   A period of observation or surveillance at any hour.
3. 3
   The eve of a religious festival in which staying awake is part of the ritual devotions.
4. 4
   A quiet demonstration in support of a cause.

Verb

1. 1
   To participate in a vigil.

Proper noun

1. 1
   A surname.