Vigil (noun)

1. A period of keeping awake during the time usually spent asleep, especially to keep watch or pray.
2. A period of watchful attention, especially a watch kept during the night as a religious observance.

Origin:

Middle english, from latin vigilia, from vigil awake, from vigere to be lively, from vigor.

Examples:

1. The town held a vigil for the victims of the tragedy.
2. She kept a vigil at her father's bedside until he passed away.
3. The church held a vigil for the souls of the deceased.
4. I will keep a vigil tonight in honor of the full moon.
5. The students held a vigil to protest against the new policy.