In area, is living (8)
I believe the answer is:
existent
'living' is the definition.
(thesaurus)
'in area is' is the wordplay.
'in' means one lot of letters goes inside another.
'area' becomes 'extent' (I've seen this before).
'extent' enclosing 'is' is 'EXISTENT'.
(Other definitions for existent that I've seen before include "Living" , "Having reality" , "Actual or current, having being" .)