Mo. Rev. Stat. § 452.850: Definitions.

As used in sections 452.850 to 452.915:

(1) "Petitioner" means a person who seeks enforcement of a child custody determination or enforcement of an order for the return of the child under the Hague Convention on the Civil Aspects of International Child Abduction;

(2) "Respondent" means a person against whom a proceeding has been commenced for enforcement of a child custody determination or enforcement of an order for the return of the child under the Hague Convention on the Civil Aspects of International Child Abduction.