Definitions for "Metagame"
Refers to all aspects of play that cannot be represented in terms of the game world, eg. game balance, plot, relationships between players.
the construct that is the game, as opposed to the things and actions existing within it. For example, the knowledge and beliefs of a character are part of the game's reality; the thoughts and beliefs of that character's player are part of the metagame, or "outer" reality. Using information known only to the player to determine a character's behavior is considered to be a metagame tactic, and should be discouraged as much as possible. "To metagame" means to use this out-of-character knowledge to make in-game decisions.
In many games there are patterns based on styles of decks. These coalesce from a communal group-think that develops as players try different strategies, and find what works. When someone comes up with the new “best deck”, someone else will come up with a deck that will beat it. This ebb and flow of deck ideas is referred to as the metagame.