Where does “خواهر” come from?
خواهر (Persian) comes from Middle Persian xwah(ar), from Proto-Iranian hwáhā, from Proto-Indo-Iranian swásā, from Proto-Indo-European swésōr, from Proto-Indo-European su-h₁ésh₂-ōr, from Proto-Indo-European h₁ésh₂r̥ — blood.
خواهر (Persian): sister; sissy
Ancestry of “خواهر”, step by step