A game in which the sum of the winnings by all the players is zero. In a zero-sum game, a gain by one player must be matched by a loss by another player. Poker is a zero-sum game if the house does not take a cut as a charge for playing.
A game in which the winnings of some players must equal the losses of the others. Zero-sum games are mentioned in a political context when it is believed that resources are limited, and every decision will produce both winners and losers. In such situations, political decisions will be made on the basis of trade-offs between competing interests.