fortress vs fort

fortress and fort both are nouns.

Word	Noun	Adjective	Verb	Adverb
fortress	Yes	No	No	No
fort	Yes	No	Yes	No

As nouns, fortress and fort are synonyms defined as:

fortress (noun)	fort (noun)
a fortified defensive structure	a fortified defensive structure
	a fortified military post where troops are stationed

fortress (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