Where does “[[ēþ]], [[eth]]” come from?

[[ēþ]], [[eth]] (Old Danish) comes from Old Norse eiðr, from Proto-Germanic aiþaz, from Proto-Indo-European oyt-.

Ancestry of “[[ēþ]], [[eth]]”, step by step

StepLanguageWordMeaning
1Old Norseeiðroath
2Proto-Germanicaiþazoath
3Proto-Indo-Europeanoyt-—

Words derived from “[[ēþ]], [[eth]]”

Every word from Proto-Indo-European oyt- →Every word from Proto-Germanic aiþaz →Every word from Old Norse eiðr →