Bible found in urban excavation (6)
I believe the answer is:
cavity
'excavation' is the definition.
(thesaurus)
'bible found in urban' is the wordplay.
'bible' becomes 'AV' (Authorised Version of the Bible).
'found in' is an insertion indicator.
'urban' becomes 'city'.
'av' going inside 'city' is 'CAVITY'.
(Other definitions for cavity that I've seen before include "Hollow place" , "A hole could mean work for the dentist" , "Destination for a filling!" , "Empty space" , "Hole, gap" .)