Where does “bei” come from?

bei (Middle English) comes from Old English bēag, from Proto-West Germanic *baug, from Proto-Germanic baugaz, from Proto-Indo-European bʰewgʰ- — to bend; curve, arch.

Ancestry of “bei”, step by step

Step	Language	Word	Meaning
1	Old English	bēag	a ring, bracelet, collar, garland, crown,...
2	Proto-West Germanic	*baug	—
3	Proto-Germanic	baugaz	a bend; bow; something bent ; circle; a ring;...
4	Proto-Indo-European	bʰewgʰ-	to bend; curve, arch

Every word from Proto-Indo-European bʰewgʰ- →

bei — Etymology, Origin & Word History | Etymology Explorer