Ordering sacks or barrels (5)
I believe the answer is:
casks
'barrels' is the definition.
(I know this)
'ordering sacks' is the wordplay.
'ordering' is an anagram indicator.
'sacks' is an anagram of 'CASKS'.
'or' acts as a link.
(Other definitions for casks that I've seen before include "vessels" , "Barrel-shaped containers for liquids" , "lots of beer" , "Large barrels" .)