DLC  

ZAM Network Wikibase™ Dictionary

Down-Loadable Content - This is used by many game publishers to describe NEW content, not part of the original core or "vanilla" game.

It may be new areas to play, new bad-guys to kill, new skills and items available, and/or new playable races.

Some DLC is release free to active subscribers but some, like an annual Expansion, usually requires some additional payment.