A river that flows for 128 miles (206 km) from West Virginia into western Pennsylvania to Pittsburgh where it joins the Allegheny River to form the Ohio River.
Definition of Monongahela River in US English:
Monongahela River
proper nounməˌnäNGɡəˌhēlə ˈrivər
A river that flows for 128 miles (206 km) from West Virginia into western Pennsylvania to Pittsburgh where it joins the Allegheny River to form the Ohio River.