Brewer's cart (4)
I believe the answer is:
dray
'brewer's cart' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for dray that I've seen before include "Cart without sides, for delivering barrels" , "Cart used for heavy loads" , "Flat-bed truck" , "Strong low cart for heavy loads" , "Brewer's horse-drawn cart" .)