In international politics, a union for joint action of various powers or states. Examples include the alliance of the European powers and the U.S. against Germany and its allies during World War II and the alliance of the NATO states against the Soviet Union and its allies during the Cold War. Many alliances rest on the principle of collective security, through which an attack on one member is considered an attack on all members. Major alliances formed after World War II include the ANZUS Pact, the Arab League, ASEAN, the Organization of American States, the Southeast Asia Treaty Organization, and the Warsaw Pact.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on alliance, visit

Seen & Heard

What made you look up alliance? Please tell us what you were reading, watching or discussing that led you here.