The term 'reserve supply' refers to a collection of items that are kept in storage for future use. STOCKPILE (9 letters), STOCK (5 letters), BACKLOG (7 letters), STORE (5 letters), spares (6 letters), and spareparts (10 letters) are all words that can be used to describe a reserve supply. A STOCKPILE is a large amount of something that is kept in reserve, while STOCK is a smaller amount of something that is kept in reserve. A BACKLOG is a collection of items that have not yet been processed or dealt with, while a STORE is a place where items are kept for future use. Spares are items that are kept in reserve in case of emergency, and spareparts are components of a larger item that are kept in reserve in case of repair.