A more thorough explanation:

A petitory action is a type of legal proceeding that seeks to establish ownership or possession of property. It is a civil or criminal judicial proceeding that can result in a judgment or decree. The action is brought by one party against another party for the enforcement or protection of a right, the redress or prevention of a wrong, or the punishment of a public offense.

For example, if two people claim ownership of a piece of land, one of them can bring a petitory action to establish their ownership. The court will then determine who has the legal right to the property and issue a judgment or decree accordingly.