Noah Webster's New International Dictionary of the English Language

1. (v. i.) Abstinence from sleep, whether at a time when sleep is customary or not; the act of keeping awake, or the state of being awake, or the state of being awake; sleeplessness; wakefulness; watch.

2. (v. i.) Hence, devotional watching; waking for prayer, or other religious exercises.

3. (v. i.) Originally, the watch kept on the night before a feast.

4. (v. i.) Later, the day and the night preceding a feast.

5. (n.) A religious service performed in the evening preceding a feast.