What is the meaning of Vigil?

An instance of keeping awake during normal sleeping hours, especially to keep watch or pray.

A period of observation or surveillance at any hour.

The eve of a religious festival in which staying awake is part of the ritual devotions.

A quiet demonstration in support of a cause.

To participate in a vigil.

awake, watching, alert

watchman, guard, sentinel; constable, fireman; angel

the watch, police, constabulary

Source: wiktionary.org