Where does “Poloni” come from?

Poloni (Cornish) comes from Latin Polonia, from Proto-Slavic poľane, from Proto-Slavic poľe, from Proto-Indo-European pleh₂- — flat.

Ancestry of “Poloni”, step by step

StepLanguageWordMeaning
1LatinPoloniaPoland
2Proto-Slavicpoľane—
3Proto-Slavicpoľefield
4Proto-Indo-Europeanpleh₂-flat
Every word from Proto-Indo-European pleh₂- →Every word from Proto-Slavic poľe →Every word from Proto-Slavic poľane →