watchtower

English Thesaurus

1. an observation tower for a lookout to watch over prisoners or watch for fires or enemies (noun.artifact)

hypernym	:	tower,
definition	:	a structure taller than its diameter; can stand alone or be attached to a larger building (noun.artifact)

hyponym	:	fire tower,
definition	:	a watchtower where a lookout is posted to watch for fires (noun.artifact)