Where does “siwojaj” come from?

siwojaj (Polish) comes from Polish jajo, from Serbo-Croatian jáje, from Proto-Slavic ȃje, from Proto-Balto-Slavic *ṓjan, from Proto-Indo-European h₂ōwyóm, from Proto-Indo-European h₂éwis — bird.

Ancestry of “siwojaj”, step by step

siwojaj traces back through two separate lines of ancestry.

via Polish jajo

StepLanguageWordMeaning
1Polishjajoegg; ovum; ball, nut
2Serbo-Croatianjájeegg
3Proto-Slavicȃjeegg amniote embryo with protective shell
4Proto-Balto-Slavic*ṓjanegg
5Proto-Indo-Europeanh₂ōwyómegg
6Proto-Indo-Europeanh₂éwisbird

via Polish Siwy

StepLanguageWordMeaning
1PolishSiwygrey-haired
2Proto-Slavicsivъgrey; hoary, grey-haired, aging
3Proto-Balto-Slavicśī́ˀwasgrey
4Proto-Indo-European(s)ḱih₃-wó-s
5Proto-Indo-European(s)ḱeh₃-darkness, shadow
Every word from Proto-Indo-European h₂éwisEvery word from Proto-Indo-European h₂ōwyómEvery word from Proto-Balto-Slavic *ṓjan