Where does “tri” come from?

tri (Proto-Slavic) comes from Proto-Balto-Slavic tríjes, from Proto-Indo-European *tréyes.

Ancestry of “tri”, step by step

StepLanguageWordMeaning
1Proto-Balto-Slavictríjesthree
2Proto-Indo-European*tréyes—

Words derived from “tri”

Every word from Proto-Indo-European *tréyes →Every word from Proto-Balto-Slavic tríjes →