Proto-Slavic *ostrovъ

→ Belarusian востраў (inherited)

→ Bulgarian остров (inherited)

→ Czech ostrov (inherited)

→ Old Church Slavonic островъ (inherited)

→ Ancient Greek ῥόος (cognate)

→ Macedonian остров (inherited)

→ Polish ostrów (inherited)

→ Romanian ostrov (derived)

→ Russian остров (inherited)

→ Serbo-Croatian острво (inherited)

→ Serbo-Croatian ostrvo (inherited)

→ Slovak ostrov (inherited)

→ Ukrainian острів (inherited)

→ Old Czech ostrov (inherited)