A big-box store (also supercenter, superstore, or megastore) is a physically large retail establishment, usually part of a chain. The term sometimes also refers, by extension, to the company that operates the store. The store may sell general dry goods in which case it is a department store, or may be limited to a particular specialty (such establishments are often called "category killers") or may also sell groceries, in which case some countries use the term hypermarket.