Origins of Tim Rice musical for radio (7)
I believe the answer is:
trannie
'radio' is the definition.
(short for transistor radio)
'origins of tim rice musical' is the wordplay.
'origins of' says to take the initial letters.
'musical' becomes 'annie' (Annie is a Broadway musical).
The first letters of 'tim rice' is 'tr'.
'tr'+'annie'='TRANNIE'
'for' is the link.
(Other definitions for trannie that I've seen before include "cross dresser" , "set of yesteryear" .)