vigil

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A watch kept during normal sleeping hours.
2. n. The act or a period of observing; surveillance.
3. n. The eve of a religious festival observed by staying awake as a devotional exercise.
4. n. Ritual devotions observed on the eve of a holy day. Often used in the plural.

Century Dictionary and Cyclopedia

1. n. The act of keeping awake; abstinence or forbearance from sleep at the natural or ordinary hours of rest; the state of being awake during the natural time for sleep; sleeplessness; wakefulness; watch: commonly in the plural.
2. n. Devotional watching; hence, devotions, services, praise, prayer, or the like performed during the customary hours of sleep; nocturnal devotions: commonly in the plural.
3. n. Eccles.: Originally, in the early church, the watch kept in a church or cemetery on the night before a feast, the time being occupied in prayer. The assembly on such occasions often leading to disorders, the custom of holding such vigils came to be abandoned in the eleventh or twelfth century. A trace of the old custom remains in the matins, lauds, and midnight mass before Christmas day.
4. n. Hence— The day and night preceding a festival; the eve or day before a festival; strictly, an eve which is a fast. Special offices or the use of the collect of the festival mark the vigil. If the day before such a festival is Sunday, the fast is transferred to the previous Saturday. Vigils are observed in the Roman Catholic, the Greek, the Anglican, and other churches.
5. n. A wake.

Wiktionary

1. n. A watch kept during normal sleeping hours, especially over the body of a recently deceased or dying person.
2. n. A period of observation or surveillance.
3. n. The eve of some religious festival in which staying awake is part of the ritual devotions.

GNU Webster's 1913

1. n. Abstinence from sleep, whether at a time when sleep is customary or not; the act of keeping awake, or the state of being awake; sleeplessness; wakefulness; watch.
2. n. Hence, devotional watching; waking for prayer, or other religious exercises.
3. n. Originally, the watch kept on the night before a feast.
4. n. Later, the day and the night preceding a feast.
5. n. A religious service performed in the evening preceding a feast.

WordNet 3.0

1. n. a purposeful surveillance to guard or observe
2. n. a period of sleeplessness
3. n. the rite of staying awake for devotional purposes (especially on the eve of a religious festival)