Sentry duty is a responsibility that involves keeping watch over a specific area or property. There are several synonyms for the term that describe this duty in different ways. Guard duty, for instance, emphasizes the protective aspect of the duty. Watch duty, on the other hand, derives from the root meaning of the word "sentry" and implies a focus on observance and attentiveness. Lookout duty is similar but also implies a degree of distance or obstruction between the sentry and the area being watched, such as standing watch on a high tower. Other synonyms include patrol duty, sentinel duty, and night watch. Each term emphasizes a different aspect of the duty but all share the common goal of security and safety.