a. A watch kept during normal sleeping hours.
b. The act or a period of observing; surveillance.
2. The eve of a religious festival observed by staying awake as a devotional exercise.
3. often vigils Ritual devotions observed on the eve of a holy day.
4. A public assembly convened, often at night, as a political protest or in support of a cause.
[Middle English vigile, a devotional watching, from Old French, from Latin vigilia, wakefulness, watch, from vigil, awake; see weg- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.