British county (5)
I believe the answer is:
shire
'british county' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for shire that I've seen before include "County (esp. in England)" , "The -----: Tolkien's hobbit-land" , "Devon maybe" , "Powerful draught horse" , "Heavy horse" .)