high hat vs opera hat

high hat and opera hat both are nouns.

Word	Noun	Adjective	Verb	Adverb
high hat	Yes	No	No	No
opera hat	Yes	No	No	No

As nouns, high hat and opera hat are synonyms defined as:

high hat and opera hat: a man's hat with a tall crown; usually covered with silk or with beaver fur

Other synonyms of high hat include beaver, dress hat, silk hat, stovepipe, top hat, topper.

high hat (noun)	opera hat (noun)
cymbals that are operated by a foot pedal	a man's hat with a tall crown; usually covered with silk or with beaver fur
a man's hat with a tall crown; usually covered with silk or with beaver fur