Where does “ʾy” come from?

ʾy (Middle Persian) comes from Proto-Iranian Háywah, from Proto-Indo-Iranian Háywas, from Proto-Indo-European óynos — one; single.

Ancestry of “ʾy”, step by step

StepLanguageWordMeaning
1Proto-IranianHáywahone
2Proto-Indo-IranianHáywasjust, only; one
3Proto-Indo-Europeanóynosone; single

Words derived from “ʾy”

Every word from Proto-Indo-European óynos →Every word from Proto-Indo-Iranian Háywas →Every word from Proto-Iranian Háywah →