Kid in sound or river (4)
I believe the answer is:
tees
'river' is the definition.
(River Tees)
'kid in sound' is the wordplay.
'kid' becomes 'tease' (I've seen this before).
'in sound' shows a homophone (sound like).
'tease' sounds like 'TEES'.
'or' is the link.
(Other definitions for tees that I've seen before include "Northern river" , "sand-hills" , "Current" , "often damaged by drivers" , "River on which Middlesbrough stands" .)