Bishop about to get one type of dairy product (4)
I believe the answer is:
brie
'type of dairy product' is the definition.
'bishop about to get one' is the wordplay.
'bishop' becomes 'B' (abbreviation for bishop in chess).
'about' becomes 're' ('re' means regarding or about).
'to get' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
're' enclosing 'i' is 'rie'.
'b'+'rie'='BRIE'
(Other definitions for brie that I've seen before include "Soft and creamy mild white cheese" , "dairy product" , "French 8 across" , "Food" , "cheese-producing region" .)