Where does “седмъ” come from?

седмъ (Old Church Slavonic) comes from Proto-Slavic sedmъ, from Proto-Balto-Slavic septmas, from Proto-Indo-European septḿ̥ — seven.

Ancestry of “седмъ”, step by step

StepLanguageWordMeaning
1Proto-Slavicsedmъseventh
2Proto-Balto-Slavicseptmas—
3Proto-Indo-Europeanseptḿ̥seven

Words derived from “седмъ”

Every word from Proto-Indo-European septḿ̥ →Every word from Proto-Balto-Slavic septmas →Every word from Proto-Slavic sedmъ →