An expansion pack is like an extra piece of a game or software that you can add to make it bigger, have new levels, features, or improvements. Full definition
Even before its release, the first expansion pack for co-op space shooter Destiny was attracting controversy. (theguardian.com)
Once the game was solid, the developers went about the business of launching a raft of new expansion packs. (ps3attitude.com)
Even though its release was paired with certain issues, the game still managed to prove a success and even release a series of expansion packs which add on to the fun. (gamenguide.com)