A zero-sum game is a situation in which the total gains and losses of the participants add up to zero. In other words, in a zero-sum game, one participant's gain is offset by the losses of the other participants.

Zero-sum games are often associated with competition, and they can be found in a variety of contexts, including business, politics, and sports. In a zero-sum game, the success of one participant is often achieved at the expense of the other participants, and the outcome is often determined by the relative skill or strategy of the players.

Examples of zero-sum games include poker, chess, and other competitive activities in which one player's gain is directly tied to the losses of the other players. In contrast, non-zero-sum games involve situations in which the total gains and losses of the participants do not add up to zero, and the outcomes may be positive or negative for all participants.