Scandinavian coin or note (3)
I believe the answer is:
ore
'scandinavian coin' is the definition.
(I've seen this in another clue)
'or note' is the wordplay.
'note' becomes 'e' (musical note).
'or'+'e'='ORE'
(Other definitions for ore that I've seen before include "15 down earth" , "tangle" , "Natural material from which metals can be extracted" , "foreign money" , "Mineral - Scandinavian money" .)