Ancillary and Pendent Jurisdiction
Definition
Constitutional concepts permitting a federal court to hear claims outside of its independent jurisdiction if they are substantially related to a claim that is within the court’s jurisdiction. Traditionally, pendent jurisdiction is exercised over nonfederal claims asserted by a plaintiff in a federal question suit, and ancillary jurisdiction involves claim or party joinder instituted by a party or nonparty. Since 1990, under 28 U.S.C. § 1367, these claims are now generally referred to as supplemental claims.