In game theory (and economic theory) a zero-sum game is a situation where one persons (or entities) gain has a corresponding loss from another person (or entity).
Initech employee 1: "Hey, everyone took big pieces of the cake now Milton doesn't have one."
Initech employee 2: "Cake is a zero sum game, man."
Initech employee 2: "Cake is a zero sum game, man."
by TheKnightWhoSaidIckyIcky February 15, 2014