Definitions

1. noun

a soldier or police officer stationed to guard a place, especially at night

“The sentry stood at attention, watching the gate.”

2. noun

a person who keeps watch or guards something

“The sentry on the ship kept a lookout for any signs of danger.”

3. noun

a mechanical device or system that controls or monitors the flow of something

“The sentry system detected the intruder and alerted the security team.”

4. noun

a figure in a play or story that serves as a guardian or protector

“The sentry in the fairy tale warned the kingdom of the impending danger.”

5. verb

to serve as a sentry or guard

“The officer sentried the perimeter of the base.”