Intervener

A party who seeks to interpose in a suit. See "Intervention." INTERVENTION (Lat. intervenio, to come between or among). In Civil Law. The act by which a third party becomes a party in a suit pending between other persons. The intervention is made either to be joined to the plaintiff, and to claim the same thing he does, or some other thing connected with it; or to join the defendant, and with him to oppose the claim of the plaintiff, which it is his interest to defeat. Poth. Proc. Civ. c. 2, sec. 6, § 3. In Modern Practice. The term Is sometimes used in the same sense as in the civil law. In English Ecclesiastical Law. The proceeding of a third person, who, not being originally a party to the suit or proceeding, but claiming an interest in the subject matter in dispute, in order the better to protect such interest, interposes his claim. 2 Chit. Prac. 492; 3 Chit. Com. Law, 633; 2 Hagg. Const. 137; 3 Phillim. Ecc. Law, 586; 1 Add. Ecc. Law, 5; 4 Hagg. Ecc. Law, 67; Dunl. Adm. Prac. 74. The intervener may come in at any stage of the cause, and even after judgment, if an appeal can be allowed on such judgment. 2 Hagg. Const. 137; 1 Eng. Ecc. Law, 480; 2 Eng. Ecc. Law, 13.

An intervener isa person who voluntarily interposes in an action or other proceeding with the leave of the COULt.