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.
© Webster 1913.