martello tower vs fort

martello tower and fort both are nouns.

Word	Noun	Adjective	Verb	Adverb
martello tower	Yes	No	No	No
fort	Yes	No	Yes	No

As nouns, fort is a hypernym of martello tower; that is, fort is a word with a broader meaning than martello tower:

Other hypernyms of martello tower include fortress.

martello tower (noun)	fort (noun)
a circular masonry fort for coastal defence	a fortified defensive structure
	a fortified military post where troops are stationed

martello tower (verb)	fort (verb)
	station (troops) in a fort
	enclose by or as if by a fortification
	gather in, or as if in, a fort, as for protection or defense