Sentry Sen"try, n.; pl. Sentires. [Probably from OF. senteret a little patch; cf. F. sentier path, and OF. sente. See Sentinel.] 1. (Mil.) A soldier placed on guard; a sentinel. 2. Guard; watch, as by a sentinel. Here toils, and death, and death's half-brother, sleep, Forms terrible to view, their sentry keep. --Dryden. Sentry box, a small house or box to cover a sentinel at his post, and shelter him from the weather.