silver certificate vs bank note

silver certificate and bank note both are nouns.

Word	Noun	Adjective	Verb	Adverb
silver certificate	Yes	No	No	No
bank note	Yes	No	No	No

As nouns, bank note is a hypernym of silver certificate; that is, bank note is a word with a broader meaning than silver certificate:

silver certificate: formerly a bank note issued by the United States Treasury and redeemable in silver
bank note: a piece of paper money (especially one issued by a central bank)

Other hypernyms of silver certificate include bank bill, banker's bill, banknote, bill, Federal Reserve note, government note, greenback, note.

silver certificate (noun)	bank note (noun)
formerly a bank note issued by the United States Treasury and redeemable in silver	a piece of paper money (especially one issued by a central bank)