Plenty of silver stocked by British store originally (4)
I believe the answer is:
bags
'plenty' is the definition.
(I've seen this before)
'silver stocked by british store originally' is the wordplay.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'stocked by' is an insertion indicator.
'originally' suggests taking the first letters.
The initial letters of 'british store' is 'bs'.
'ag' put within 'bs' is 'BAGS'.
'of' is the link.
(Other definitions for bags that I've seen before include "Items of luggage" , "Containers for carrying, informally plenty" , "Takes unilaterally" , "I claim" , "Childishly claims" .)