Where does “pr̥tʰúṣ” come from?

pr̥tʰúṣ (Proto-Indo-Aryan) comes from Proto-Indo-Iranian pr̥tʰúš, from Proto-Indo-European pléth₂us, from Proto-Indo-European pleth₂- — flat.

Ancestry of “pr̥tʰúṣ”, step by step

StepLanguageWordMeaning
1Proto-Indo-Iranianpr̥tʰúšbroad, wide
2Proto-Indo-Europeanpléth₂usflat, broad
3Proto-Indo-Europeanpleth₂-flat
Every word from Proto-Indo-European pleth₂- →Every word from Proto-Indo-European pléth₂us →Every word from Proto-Indo-Iranian pr̥tʰúš →