Department stores ring warehouse (5)
I believe the answer is:
depot
'warehouse' is the definition.
(thesaurus)
'department stores ring' is the wordplay.
'department' becomes 'dept'.
'stores' is an insertion indicator.
'ring' becomes 'o'.
'dept' placed around 'o' is 'DEPOT'.
(Other definitions for depot that I've seen before include "Supply base" , "Bus station or warehouse" , "Storehouse, repository" , "Storehouse or warehouse" , "Large storage site" .)