Expansion pack

In terms of software, an expansion pack is a piece or collection of pieces of software which add functionality to preexisting software. Expansion packs are also often called "Downloadable Content" (DLC). Expansion packs are commonly used by video games--consumers can buy the base game and use it as-is, but they can also buy one or more expansion packs to expand the game by adding additional levels or other content. Expansion packs are also sometimes used buy other complex software, especially corporate out-of-the-box software.