Commissary (store)

A commissary is a store for provisions. The United States Defense Commissary Agency operates commissaries that are similar to supermarkets, providing service members with most of the same available in the United States regardless of where they are stationed abroad. Commissaries sell primarily grocery articles; other items can be purchased at a base exchange (BX) or post exchange (PX).

Examples
A prison commissary is often present in prisons, There are also commissaries at the United Nations, and on  filming locations.