Noun

1. A small portable timepiece
2. A period of time (4 or 2 hours) during which some of a ship's crew are on duty
3. A purposeful surveillance to guard or observe
4. The period during which someone (especially a guard) is on duty
5. A person employed to keep watch for some anticipated event
6. The rite of staying awake for devotional purposes (especially on the eve of a religious festival)

Verb

1. Look attentively
2. Follow with the eyes or the mind
3. See or watch
4. Observe with attention
5. Be vigilant, be on the lookout or be careful
6. Observe or determine by looking
7. Find out, learn, or determine with certainty, usually by making an inquiry or other effort