The old name for money (3)
I believe the answer is:
yen
'money' is the definition.
(Japanese currency)
'the old name' is the wordplay.
'the old' becomes 'ye'.
'name' becomes 'n' (common abbreviation e.g. on forms).
'ye'+'n'='YEN'
'for' is the link.
(Other definitions for yen that I've seen before include "money in Tokyo" , "foreign currency" , "Unit of money in Japan" , "change in East" , "Longing for a currency unit" .)