Where does “Oreavu” come from?

Oreavu (Romanian) comes from Old East Slavic орѣхъ, from Proto-Slavic orěxъ, from Proto-Indo-European areyis-.

Ancestry of “Oreavu”, step by step

StepLanguageWordMeaning
1Old East Slavicорѣхъ—
2Proto-Slavicorěxъnut; walnut
3Proto-Indo-Europeanareyis-—
Every word from Proto-Indo-European areyis- →Every word from Proto-Slavic orěxъ →Every word from Old East Slavic орѣхъ →