сахаръ (Old East Slavic) comes from Ancient Greek σάκχαρ, from Sanskrit शर्करा, from Proto-Indo-Aryan śárkaraH, from Proto-Indo-Iranian ćárkaraH, from Proto-Indo-European ḱorkeh₂ — gravel, boulder; boulder; gravel.
Ancestry of “сахаръ”, step by step
сахаръ traces back through 3 separate lines of ancestry.