Sentry's duty is to vigilantly WATCH and PATROL an area. This job requires a high level of alertness and attention to detail, as the SENTRY is responsible for protecting the area from any potential threats. The term 'SENTRY' is derived from the Latin word 'sentinum, ' which means 'guard post.' Sentries are often employed in military and security roles, where they are tasked with keeping a lookout for any suspicious activity or potential danger.