Where does “HD” come from?

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

Ancestry of “HD”, step by step

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

Words derived from “HD”

Every word from Proto-Indo-European óynos →Every word from Proto-Indo-Iranian Háywas →Every word from Proto-Iranian Háywah →
HD — Etymology, Origin & Word History | Etymology Explorer