I. stock ‧ pile 1 /ˈstɒkpaɪl $ ˈstɑːk-/ BrE AmE noun [countable]
a large supply of things that is kept ready for use in the future SYN store
stockpile of
a stockpile of nuclear weapons
II. stockpile 2 BrE AmE verb [transitive]
to keep adding to a supply of goods, weapons etc that you are keeping ready to use if you need them in the future:
An enormous volume of explosives was stockpiled inside one of the buildings.