Other terms for the concept are module and, in certain games' marketing, adventure. Board games and tabletop RPGs may have been marketing expansions since the 1970s, and video games have been releasing expansion packs since the 1980s, early examples being the Dragon Slayer games Xanadu Scenario II and Sorcerian. While board game expansions are typically designed by the original creator, video game developers sometimes contract out development of the expansion pack to a third-party company, it may choose to develop the expansion itself, or it may do both.
These add-ons usually add new game areas, weapons, objects, characters, or an extended storyline to an already-released game. An expansion pack, expansion set, supplement, or simply expansion is an addition to an existing role-playing game, tabletop game, video game or collectible card game.