banknote vs bank bill

banknote and bank bill both are nouns.

Word	Noun	Adjective	Verb	Adverb
banknote	Yes	No	No	No
bank bill	Yes	No	No	No

As nouns, banknote and bank bill are synonyms defined as:

banknote and bank bill: a piece of paper money (especially one issued by a central bank)

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

banknote (noun)	bank bill (noun)
a piece of paper money (especially one issued by a central bank)	a piece of paper money (especially one issued by a central bank)