In International Law

A contract, treaty, or league between two sovereigns or states, made to insure their safety and common defense. Alliances are defensive, or offensive. (1) Defensive alliances are those in which a nation agrees to defend her ally in case she is attacked. (2) Offensive alliances are. those in which nations unite for the purpose of making an attack, or jointly waging the war against another nation. Alliances may be at the same time offensive and defensive; and most offensive alliances are of this character. Vattel, bk. 3, c. 6, § 79; 2 Dall. (Pa.) 15.

Defined under Alleging Diminution in The Cyclopedic Law Dictionary.