twenty vs Federal Reserve note

twenty and Federal Reserve note both are nouns.

Word	Noun	Adjective	Verb	Adverb
twenty	Yes	Yes	No	No
Federal Reserve note	Yes	No	No	No

As nouns, Federal Reserve note is a hypernym of twenty; that is, Federal Reserve note is a word with a broader meaning than twenty:

twenty: a United States bill worth 20 dollars
Federal Reserve note: a piece of paper money (especially one issued by a central bank)

Other hypernyms of twenty include bank bill, bank note, banker's bill, banknote, bill, government note, greenback, note.

twenty (noun)	Federal Reserve note (noun)
a United States bill worth 20 dollars	a piece of paper money (especially one issued by a central bank)
the cardinal number that is the sum of nineteen and one

twenty (adjective)	Federal Reserve note (adjective)
denoting a quantity consisting of 20 items or units