“Prisoner’s dilemma” refers, in game theory, to a configuration of payoffs that gives both players dominant incentives—in the absence of an enforceable agreement to the contrary—to choose strategies that together yield both players a less desirable outcome than if both had made opposite choices. The name derives from the problem of two prisoners, separately interrogated, who may confess to a moderate crime in common or accuse each other of a heavy crime, an accuser going free unless himself accused, the accused one or ones receiving heavy sentences.

Thomas C. Schelling, The Strategy of Conflict, loc. 814