stockpile

Short definition from Wiktionary

Noun

1. 1
   A supply (especially a large one) of something kept for future use, specifically in case the cost of the item increases or if there a shortage.
2. 2
   A supply (especially a large one) of something kept for future use, specifically in case the cost of the item increases or if there a shortage: A supply of nuclear weapons kept by a country; a nuclear stockpile.
3. 3
   A pile of coal or ore heaped up on the ground after it has been mined.

Verb

1. 1
   To accumulate or build up a supply of (something).
2. 2
   To accumulate or build up a supply of (something): To build up a stock of (nuclear weapons).
3. 3
   To heap up piles of (coal or ore) on the ground after it has been mined.
4. 4
   To build up a supply; to accumulate.