See! I see cod battered! (7)
I believe the answer is:
'see' is the definition.
(both can mean a bishop's associated area)
'i see cod battered' is the wordplay.
'battered' indicates an anagram.
'iseecod' anagrammed gives 'DIOCESE'.
(Other definitions for diocese that I've seen before include "Bishop's see" , "Bishop's responsibility" , "District under a bishop's authority" , "I see cod (anag)" , "Bishop's region" .)