Names for the number 0 in English no authoritative evidence that there has ever been any such word in Scots in the first place. According to the Oxford English Dictionary, the first use of the word "love" in English to mean "zero" was to define how a game was to be played, rather than the score in the game itself. Gambling games could be played for stakes (money) or "for love (of the game)", i.e. for zero stakes. The first such recorded usage quoted in the OED was in 1678. The shift in meaning from "zero stakes" to "zero score" is not an enormous conceptual leap, and
Zero-sum game a situation in which the interacting parties' aggregate gains and losses can be less than or more than zero. A zero-sum game is also called a "strictly competitive" game while non-zero-sum games can be either competitive or non-competitive. Zero-sum games are most often solved with the minimax theorem which is closely related to linear programming duality, or with Nash equilibrium. The zero-sum property (if one gains, another loses) means that any result of a zero-sum situation is Pareto optimal. Generally, any game where all strategies are Pareto optimal is called a conflict game. Zero-sum games are a specific example of