A lookout (vantage point with a view of the surrounding area)
A place where stars, planets and other celestial bodies are observed, usually through a telescope; also place for observing meteorological or other natural phenomena.
A watchtower.
A animal like a marmot tasked with alerting the pack to danger.
Sentry duty; time spent being a sentry.
A guard, particularly on duty at the entrance to a military base.
A form of drag to be towed underwater, which on striking bottom is upset and rises to the surface.