ex relatione

preposition | \ ˈeks-ri-ˌlā-shē-ˈō-nē, -re-ˌlä-tē-ˈō-nā \ | ex re·la·tio·ne

1. : by or on the relation or information of

   Note: The abbreviation for ex relatione, ex rel., is used in the title of informations and special proceedings to designate the interested individual, called the relator, at whose instance the state or public officer is acting.