a river in the E central US, rising in the Appalachian Mountains of West Virginia: flows northeast, then generally southeast to Chesapeake Bay. Length (from the confluence of headstreams): 462 km (287 miles)
Potomac in American English
(pəˈtoʊmək)
river in the E U.S., forming a boundary of W.Va., Md., & Va., and flowing into Chesapeake Bay: 285 mi (459 km)