This has never been correct, it isn't an acronym, it's a prefix. Metagaming is the art of learning how players typically play a game and has been a concept for a long time. The etymology is simple, the greek "Meta-" meaning beyond and "metagame" referring to the way people play a game developing alongside a game. Look at dota 2, the metagame shifts in large ways when the map does not relatively frequently. When we talk about metagaming in card games, it's in reference to which cards see the most play regardless of their impact on the game.