Where does “былина” come from?

былина (Old East Slavic) comes from Old East Slavic бꙑти, from Proto-Slavic *byti, from Proto-Balto-Slavic bū́ˀtei, from Proto-Indo-European bʰuH- — to become, grow, appear.

Ancestry of “былина”, step by step

StepLanguageWordMeaning
1Old East Slavicбꙑтиto be
2Proto-Slavic*byti—
3Proto-Balto-Slavicbū́ˀteito be
4Proto-Indo-EuropeanbʰuH-to become, grow, appear

Words derived from “былина”

Every word from Proto-Indo-European bʰuH- →Every word from Proto-Balto-Slavic bū́ˀtei →Every word from Proto-Slavic *byti →