A river of the eastern US, which rises in the Appalachian Mountains in West Virginia and flows about 459 km (285 miles) through Washington DC into Chesapeake Bay on the Atlantic coast.
Definition of Potomac in US English:
Potomac
proper nounpəˈtōmək
A river of the eastern US that rises in the Appalachian Mountains in West Virginia and flows about 285 miles (459 km) through Washington, DC into Chesapeake Bay.