Cause of action: bundle of operative facts required to establish a party's entitlement to judicial remedy and jurisdiction. Cause of action denotes the set of operative facts a plaintiff must prove to obtain judicial relief, comprising every fact necessary for the plaintiff's case rather than each piece of evidentiary proof. It includes the defendant's act giving rise to the grievance and may be viewed narrowly as the immediate infraction or broadly as the infraction coupled with the right; only the material facts necessary to support the relief sought need be pleaded and proved for jurisdictional and procedural purposes.