Pre-euro Spanish coin (6)
I believe the answer is:
peseta
'pre-euro spanish coin' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for peseta that I've seen before include "Previous Spanish money unit" , "Old bread" , "Spain's former currency unit" , "Old Spanish unit of money" , "Coin from the sea pet" .)