Milk measure (4)
I believe the answer is:
pint
'milk measure' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pint that I've seen before include "Liquid measure" , "Liquid meassure - four gills" , "Glass of beer (colloq.)" , "The working man's drink measure" , "Unit of beer" .)