Peace means societal friendship and harmony in the absence of hostility and violence. In a social sense, peace is commonly used to mean a lack of conflict and freedom from fear of violence between individuals or groups.

Proponents of democratic peace theory argue that both electoral and republican forms of democracy are hesitant to engage in armed conflict with other identified democracies. Different advocates of this theory suggest that several factors are responsible for motivating peace between democratic states. Individual theorists maintain "monadic" forms of this theory ; "dyadic" forms of this theory ; and "systemic" forms of this theory.