(geology) A fast-flowing river characterized by a deep, narrow erosion pattern forming a V-shaped channel or valley.

Any marine turtle that inhabits rivers.

A city in Bristol County, Massachusetts, United States. / A river in South Dakota, United States.

(literally) A rat that lives on or along a river. / (chiefly derogatory) A lower-class person living on or along a river.

A river in the United States that flows through upstate New York down the Hudson Valley into the Atlantic Ocean.

(US, idiomatic) To prison.

The longest river in South Africa.

plural of river rat

A river that enters a sea or estuary and is this affected by tides; at times, water will flow upstream.

The European river lamprey (Lampetra fluviatilis).