Game mechanic in the context of "Expansion packs"

An expansion pack, expansion set, supplement, or simply expansion, is an addition to an existing role-playing game, tabletop game, video game, collectible card game or miniature wargame. An expansion may introduce new rules or game mechanics that augment the original game and add more variety to playing it. In the case of video games, they typically add new game areas, weapons, objects, characters, adventures or an extended storyline to an already-released game. In tabletop role-playing games, they might take the form of a campaign setting or a stand-alone adventure for players to experience.

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.