(APC) (am'byū-lă-tōr-ē pā'mĕnt klas'i-fi-kā'shŭn) In U.S. medical care, a system for grouping outpatient services provided by hospitals on the basis of similarity of costs and clinical indications; used by the Centers for Medicare and Medicaid Services to set the rates at which it will reimburse hospitals for outpatient care. AcronymsSeeAPC