From earlier sentrie, sentery, of uncertain origin. Perhaps an alteration of sentinel or sanctuary; or perhaps from Old French senteret (“a path”), diminutive of sentier, from Medieval Latin semitarius (“a path”).
sentry (plural sentries)
- A guard, particularly on duty at the entrance to a military base.
- (uncountable) Sentry duty; time spent being a sentry.
- (nautical) A form of drag to be towed underwater, which on striking bottom is upset and rises to the surface.
- A watchtower.
- A animal like a marmot tasked with alerting the pack to danger.
- (nautical drag): kite