What is Aid Prayer?

Legal Definition
English law. A petition to the court calling in help from another person who has an interest in the matter in dispute. For example, a tenant for life, by the courtesy or for years, being impleaded, may pray aid of him in reversion; that is, desire the court that he may be called by writ, to allege what he thinks proper for the maintenance of the right of the person calling him, and of his own. F. N. B. 60; Cowel.
-- Bouviers Law Dictionary
Legal Definition
In English practice. A proccedmg formerly made use of, by way of petition in court, praying in aid of the tenant for life, etc., from the reversioner or remainder-man, when the title to the inheritance was in question. It was a plea in suspension of the action. 3 Bl. Comm. 300.
-- Black's Law Dictionary
Legal Definition
A request for assistance of another to help a party to a real action to plead because of the feebleness of his own estate. See 3 Bl. Comm. 300.
-- Ballentine's Law Dictionary