Coat turning up in river (3)
I believe the answer is:
cam
'river' is the definition.
(river in Cambridge, England)
'coat turning up' is the wordplay.
'coat' becomes 'mac' (mac is a kind of coat).
'turning up' says the letters should be written backwards.
'mac' in reverse letter order is 'CAM'.
'in' is the link.
(Other definitions for cam that I've seen before include "English river" , "Rotating mechanism" , "running through university city?" , "River also called Granta" , "Part of engine" .)