Where does “siwasa” come from?

siwasa (Polish) comes from Polish siwas, from Polish Siwy, from Proto-Slavic sivъ, from Proto-Balto-Slavic śī́ˀwas, from Proto-Indo-European (s)ḱih₃-wó-s, from Proto-Indo-European (s)ḱeh₃- — darkness, shadow.

Ancestry of “siwasa”, step by step

StepLanguageWordMeaning
1Polishsiwasgray stallion
2PolishSiwygrey-haired
3Proto-Slavicsivъgrey; hoary, grey-haired, aging
4Proto-Balto-Slavicśī́ˀwasgrey
5Proto-Indo-European(s)ḱih₃-wó-s—
6Proto-Indo-European(s)ḱeh₃-darkness, shadow
Every word from Proto-Indo-European (s)ḱeh₃- →Every word from Proto-Indo-European (s)ḱih₃-wó-s →Every word from Proto-Balto-Slavic śī́ˀwas →