watchtower

An observation tower on which a guard or lookout is stationed to keep watch, as for enemies, for forest fires, or over prisoners.

A tower on which a sentinel is placed to watch for enemies, for the approach of danger, etc.

A tower in which a sentinel is placed to watch for enemies, the approach of danger, or the like.

an observation tower, in which a lookout keeps watch over prisoners, or looks out for fires etc

an observation tower for a lookout to watch over prisoners or watch for fires or enemies