Sentinel

sen′ti-nel, n. a soldier or soldier-marine at a point with the duty of watching for the approach of an enemy, or guarding the gun-park, camp, magazine, or other locality: a sentry.— adj. acting as a sentinel.— v.t. to watch over, as a sentinel.— adj. Sen′tinelled , furnished with a sentinel.— Sentinel crab , a crab of the Indian Ocean with long eye-stalks. [Fr. sentinelle —It. sent in ell a , a watch, prob. the L. sent in at or , one who pumps bilge-water out of a ship— sent in a , the hold of a ship. Others explain Fr. sentinelle as a dim. of sentier , a path—Low L. semitar i us —L. semita , a footpath.]