Olza (river)
 About this sound Olza (Czech: Olše German: Olsa) is a river in Poland and the Czech Republic the right tributary of the Oder River. It flows from the Silesian Beskids through southern Cieszyn Silesia in Poland and Frýdek-Místek and Karviná districts of the Czech Republic often forming the border with Poland. It flows into the Oder River north of Bohumín.