EU currency (4)
(Other definitions for euro that I've seen before include "Currency of France" , "The Vatican's currency" , "Currency of Greece" , "wallaroo" , "Coin issued Jan first, two thousand and two" .)
'eu currency' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for euros that I've seen before include "Rouse (anag.)" , "money" , "EU currency" , "Continental coins" , "French coins and notes" .)