bowler hat vs hat

bowler hat and hat both are nouns.

Word	Noun	Adjective	Verb	Adverb
bowler hat	Yes	No	No	No
hat	Yes	No	Yes	No

As nouns, hat is a hypernym of bowler hat; that is, hat is a word with a broader meaning than bowler hat:

bowler hat: a felt hat that is round and hard with a narrow brim
hat: headdress that protects the head from bad weather; has shaped crown and usually a brim

Other hypernyms of bowler hat include chapeau, lid.

bowler hat (noun)	hat (noun)
a felt hat that is round and hard with a narrow brim	an informal term for a person's role
	headdress that protects the head from bad weather; has shaped crown and usually a brim

bowler hat (verb)	hat (verb)
	put on or wear a hat
	furnish with a hat