Division's dry approaching hill (6)
I believe the answer is:
sector
'division's' is the definition.
(thesaurus)
'dry approaching hill' is the wordplay.
'dry' becomes 'sec' ('sec' can be similar in meaning to 'dry').
'approaching' means one lot of letters go next to another.
'hill' becomes 'tor' (tor is a kind of hill).
'sec'+'tor'='SECTOR'
(Other definitions for sector that I've seen before include "region" , "A body of people who form part of society or economy" , "District" , "Corset (anag) - part of a circle" , "Escort in zone" .)