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

(US, idiomatic) To prison.

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

plural of river rat

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

The longest river in South Africa.

plural of river turtle

black birch (Betula nigra) / red birch (Betula occidentalis)

(informal) A nickname for Pittsburgh. / (Pittsburgh, Pennsylvania, USA, North America); A city in Pennsylvania, United States. / (informal) A nickname for Trois Rivieres.

(chiefly US) A raft, kayak, or similar watercraft used especially for traveling with the current of a river in a swift manner. / (chiefly US) A person who uses such a watercraft.