Metagaming is any strategy, action or method used in a game which transcends a prescribed ruleset, uses external factors to affect the game, or goes beyond the supposed limits or environment set by the game. Another definition refers to the game universe outside of the game itself. Metagaming differs from strategy in that metagaming is making decisions based upon out of game knowledge, whereas strategies are decisions made based upon in-game actions and knowledge.
In simple terms, it is the use of out-of-game information or resources to affect one’s in-game decisions.
Recently the term metagame has come to be used by PC Gaming shoutcasters to describe an emergent methodology that is a subset of the basic strategy necessary to play the game at a high level. The definitions of this term are varied but can include “pre-game” theory, behavior prediction, or “ad hoc strategy” depending on the game being played. An example of this would be in StarCraft where a player’s previous matches with the same opponent have given them insight into that player’s playstyle and may cause them to make certain decisions which would otherwise seem inferior.