Magic: the Gathering is a game, a form of competitive activity played according to certain rules. Specifically, it is a turn-based trading card game.
A game is also single portion of play forming a scoring unit in a match between (at least) two players. While you have full control of the selection of your own cards, your deck never exists in a vacuum. One half of a game of Magic is a constant, and the other is a variable that changes with every opponent.
An object is “outside the game” if it isn’t in any of the game’s zones.