silk hat vs high hat

silk hat and high hat both are nouns.

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

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

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

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

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