DEFINITION: A “non-zero-sum game” is a type of two-sided game—in the mathematical, game-theoretic sense of the word “game”—in which a positive outcome for one side may correspond to a positive outcome for the other side, as well
In colloquial speech, a non-zero-sum game is known as a “win-win” situation.
The opposite of a non-zero-sum game is a zero-sum game.
ETYMOLOGY: The phrase “non-zero-sum” derives from the fact that the sum of the outcomes of the game for the two sides may attain values other than zero.
For example, in a non-zero-sum game, if Side A achieves an outcome of +n, then Side B may also achieve a positive outcome, say, +m. The point being that, generally speaking, n + m ≠ 0.
USAGE: In economics, it is important to remember that most situations involving production, investment, income, profit, employment, wages, and so on are non-zero-sum in nature.
Which is to say that it is perfectly possible—indeed, it is an everyday occurrence—that what makes the factory-owner better off makes the worker better off, as well.
It is relatively seldom that true zero-sum situations are encountered in everyday economic life—as opposed to the abstract theory and the political rhetoric surrounding economic decisions and policy-making.
For further discussion, see the article zero-sum game.