Former French coin (3)
'former french coin' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for sou that I've seen before include "bit of money" , "Old Fr. coin; sounds like entreat" , "Paltry sum" , "Tiny amount of money" , "Former small French coin" .)
'former french coin' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ecu that I've seen before include "Old European currency unit" , "Former European currency" , "Former name for euro" , "Original name of euro" , "Old gold coin" .)