Latin: A citation or summons to court. Citatio ad reassumendam eausam. A summons to take up the cause. A process, in the civil law, which issued when one of the parties to a suit died before its determination, for the plaintiff against the defendant’s heir, or for the plaintiff’s heir against the defendant, as the case might be; analogous to a modern bill of revivor. Citatio est de jnri natural!. A summons is by natural right. Cases in Banco Regis Wm. III. 453.