Race around some land (4)
I believe the answer is:
acre
'some land' is the definition.
(unit of land)
'race around' is the wordplay.
'around' is an anagram indicator.
'race' is an anagram of 'ACRE'.
(Other definitions for acre that I've seen before include "Care about the piece of land" , "Mediterranean port" , "stretch of land" , "Unit of area - Israeli port" , "Square measure of land" .)