Where does “Belous” come from?

Belous (English) comes from Russian Белоус, from Old East Slavic *бѣлоѫсъ, from Proto-Slavic *běloǫsъ, from Proto-Slavic bělъ, from Proto-Indo-European bʰēlHs — white surface or stain.

Ancestry of “Belous”, step by step

StepLanguageWordMeaning
1RussianБелоусmatgrass (Nardus stricta)
2Old East Slavic*бѣлоѫсъ—
3Proto-Slavic*běloǫsъwhite-moustached, whitebeard
4Proto-Slavicbělъwhite
5Proto-Indo-EuropeanbʰēlHswhite surface or stain
Every word from Proto-Indo-European bʰēlHs →Every word from Proto-Slavic bělъ →Every word from Proto-Slavic *běloǫsъ →