silk hat vs chapeau

silk hat and chapeau both are nouns.

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

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

silk hat: a man's hat with a tall crown; usually covered with silk or with beaver fur
chapeau: headdress that protects the head from bad weather; has shaped crown and usually a brim

Other hypernyms of silk hat include hat, lid, man's clothing.

silk hat (noun)	chapeau (noun)
a man's hat with a tall crown; usually covered with silk or with beaver fur	headdress that protects the head from bad weather; has shaped crown and usually a brim