folding money vs currency

folding money and currency both are nouns.

Word	Noun	Adjective	Verb	Adverb
folding money	Yes	No	No	No
currency	Yes	No	No	No

As nouns, currency is a hypernym of folding money; that is, currency is a word with a broader meaning than folding money:

folding money: currency issued by a government or central bank and consisting of printed paper that can circulate as a substitute for specie
currency: the metal or paper medium of exchange that is presently used

folding money (noun)	currency (noun)
currency issued by a government or central bank and consisting of printed paper that can circulate as a substitute for specie	the property of belonging to the present time
	general acceptance or use
	the metal or paper medium of exchange that is presently used