banknote vs bank note

banknote and bank note both are nouns.

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

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

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

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

banknote (noun)	bank note (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)