Dry, exposed rock in area (6)
I believe the answer is:
sector
'area' is the definition.
(sector is a kind of area)
'dry exposed rock' is the wordplay.
'dry' becomes 'sec' (similar in meaning).
'exposed rock' becomes 'tor'.
'sec'+'tor'='SECTOR'
'in' is the link.
(Other definitions for sector that I've seen before include "region" , "Division of a nation's economy" , "Escort in zone" , "Area covered by corset" , "Distinct area or portion" .)