Definition of Oder river

The Oder (known in Czech, Slovak and Polish as Odra) is a river in Central Europe. It begins in the Czech Republic and flows through western Poland, later forming the northern 187 km of the border between Poland and Germany, part of the Oder-Neisse line. The river ultimately flows into the Szczecin Lagoon north of Szczecin and then into three branches (Dziwna, Swina and Peene) that empty into the Baltic Sea.