OOC  

ZAM Network Wikibase™ Dictionary

Out-of-Character is a phrase specific to Role Playing. It means saying something, as an aside, that refers to topics or knowledge that is outside of the game world.

Some games, such as EverQuest II, have a separate channel of /OOC speech (so it can be ignored if desired). In other games it is accepted practice to preface any OOC comments with a prefix, such as [OOC] or OOC: as a warning to hardcore RPers that the statement should be ignored.