Where does “trithing” come from?

trithing (Middle English) comes from Old English þriðing, from Old Norse þriðjungr, from Proto-Germanic þridjô, from Proto-Indo-European tretyós, from Proto-Indo-European tr̥tyós, from Proto-Indo-European tréyes — three.

Ancestry of “trithing”, step by step

StepLanguageWordMeaning
1Old Englishþriðing—
2Old Norseþriðjungrthird part
3Proto-Germanicþridjôthird
4Proto-Indo-Europeantretyós—
5Proto-Indo-Europeantr̥tyósthird
6Proto-Indo-Europeantréyesthree

Words derived from “trithing”

Every word from Proto-Indo-European tréyes →Every word from Proto-Indo-European tr̥tyós →Every word from Proto-Indo-European tretyós →