silk hat vs top hat

silk hat and top hat both are nouns.

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

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

silk hat and top 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, high hat, opera hat, stovepipe, topper.

silk hat (noun)	top hat (noun)
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