The union or connection of two persons or families by marriage, which is also called affinity. This is derived from the Latin preposition ad and ligare, to bind.
International Law. A contract, treaty, or league between two sovereigns or states, made to insure their safety and common defence.
Alliances made for warlike purposes are divided in general into defensive and offensive; in the former the nation only engages to defend her ally in case he be attacked; in the latter she unites with him for the purpose of making an attack, or jointly waging the war against another nation. Some alliances are both offensive and defensive; and there seldom is an offensive alliance which is not also defensive.