bowler hat vs derby

bowler hat and derby both are nouns.

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

As nouns, bowler hat and derby are synonyms defined as:

bowler hat and derby: a felt hat that is round and hard with a narrow brim

Other synonyms of bowler hat include bowler, derby hat, plug hat.

bowler hat (noun)	derby (noun)
a felt hat that is round and hard with a narrow brim	a felt hat that is round and hard with a narrow brim