Where does “трэці” come from?
трэці (Belarusian) comes from Proto-Slavic tretь, from Proto-Balto-Slavic tretias, from Proto-Balto-Slavic tirtias, from Proto-Indo-European tr̥tyos, from Proto-Indo-European *tréyes.
трэці (Belarusian): third
Ancestry of “трэці”, step by step