Located where seen, we hear (5)
I believe the answer is:
sited
'located' is the definition.
('site' can be a synonym of 'locate')
'seen we hear' is the wordplay.
'seen' becomes 'sighted' (I've seen this before).
'we hear' shows a homophone (sound like).
'sighted' sounds like 'SITED'.
'where' is the link.
(Other definitions for sited that I've seen before include "installed" , "Placed, located" , "Put" , "Positioned" , "Situated" .)