Where does “þrī” come from?

þrī (Old Swedish) comes from Old Norse þrír, from Proto-Norse ᚦᚱᛁᛃᛟᛉ, from Proto-Germanic þrīz, from Proto-Indo-European *tréyes.

Ancestry of “þrī”, step by step

StepLanguageWordMeaning
1Old Norseþrírthree
2Proto-Norseᚦᚱᛁᛃᛟᛉthree
3Proto-Germanicþrīzthree
4Proto-Indo-European*tréyes—
Every word from Proto-Indo-European *tréyes →Every word from Proto-Germanic þrīz →Every word from Proto-Norse ᚦᚱᛁᛃᛟᛉ →