INTERVENTION, civil law. The act by which a third party becomes a party in a suit pending between other persons.
2. 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. Proced. Civ. lere part. ch. 2, s. 6, 3. In the English ecclesiastical courts, the same term is used in the same sense.
3. When a third person, not originally a party to the suit or proceeding, but claiming an interest in the subject-matter in dispute, may, in order the better to protect such interest, interpose his claim, which proceeding is termed intervention. 2 Chit. Pr. 492; 3 Chit. Com. Law, 633; 2 Hagg. Cons. R. 137; 3 Phillim. R. 586; 1 Addams, R. 5; Ought. tit. 14; 4 Hagg. Eccl. R. 67 Dual. Ad. Pr. 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. Cons. R. 137: 1 Eng. feel. R. 480; 2 E.g. Eccl. R. 13.