Hidden stores, we hear, for crowds (6)
I believe the answer is:
hordes
'for crowds' is the definition.
(horde is a kind of crowd)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for hordes that I've seen before include "large numbers" , "Huge noisy crowds" , "Horsed around with the multitudes" , "Mobs of people in Rhodes" , "Large moving crowds" .)