The term 'Sentry' is used to describe a person or group of people who are responsible for watching over and protecting a certain area. This could include a WATCH, PROTECTOR, WATCHMAN, GATEKEEPER, gateman, LOOKOUT, GUARD, or SENTINEL. A WATCH is a person who is assigned to observe and report any suspicious activity. A PROTECTOR is someone who is responsible for safeguarding an area or person from harm. A WATCHMAN is a person who is assigned to keep WATCH over a certain area. A GATEKEEPER is someone who is responsible for controlling access to a certain area. A gateman is a person who is assigned to open and close a gate. A LOOKOUT is a person who is assigned to look out for any potential danger. A GUARD is a person who is assigned to protect a certain area or person. A SENTINEL is a person who is assigned to stand GUARD and WATCH over a certain area.