- (n.) Watch; guard.
- (v.t.) To furnish with a sentinel; to place under the guard of a sentinel or sentinels.
- (v.t.) To watch over like a sentinel.
- (n.) A marine crab (Podophthalmus vigil) native of the Indian Ocean, remarkable for the great length of its eyestalks; -- called also sentinel crab.
- (n.) One who watches or guards; specifically (Mil.), a soldier set to guard an army, camp or other place, from surprise, to observe the approach of danger, and give notice of it; a sentry.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). sentinel. Retrieved September 22, 2026, from http://smartdefine.org/sentinel/definitions/2060470 |
| Chicago | Webster's. 2011. "sentinel" http://smartdefine.org/sentinel/definitions/2060470 (accessed September 22, 2026). |
| Harvard | Webster's 2011, sentinel, Smart Define, viewed 22 September, 2026, <http://smartdefine.org/sentinel/definitions/2060470>. |
| MLA | Webster's. "sentinel" 28 May 2011. Web. 22 September 2026. <http://smartdefine.org/sentinel/definitions/2060470> |