A volume in Charleston say for early payment (7)
I believe the answer is:
advance
'early payment' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'a volume in charleston say' is the wordplay.
'volume' becomes 'v' (abbreviation for volume in book titles).
'in' is an insertion indicator.
'charleston say' becomes 'dance' (charleston is a kind of dance).
'v' placed within 'dance' is 'dvance'.
'a'+'dvance'='ADVANCE'
'for' is the link.
Can you help me to learn more?
(Other definitions for advance that I've seen before include "borrowed money" , "Move froward as army does" , "capital" , "Move along" , "Payment ahead of due date (1'7)" .)