Stratford's river (4)
I believe the answer is:
avon
'stratford's river' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for avon that I've seen before include "Bath's river" , "Bristol's river" , "River flowing through Shakespeare's Stratford" , "English river flowing through Stratford" , "River of the Bard" .)