- a sentinel; esp., any of the men of a military guard posted to guard against, and warn of, danger
- Now Rare guard or watch: to keep sentry
Origin of sentryfrom uncertain or unknown; perhaps obsolete centrinell, variant, variety of sentinel
- A guard, especially a soldier posted at a given spot to prevent the passage of unauthorized persons.
- The duty of a sentry; watch.
Origin of sentryPerhaps alteration of obsolete sentrinel variant of sentinel