Where does “арт” come from?

арт (Ossetian) comes from Ossetian атр, from Proto-Iranian *HáHtr̥š, from Proto-Indo-Iranian *HáHtr̥š, from Proto-Indo-European h₂eh₁ter- — fire.

арт (Ossetian): fire; campfire

Definitions

Step	Language	Word	Meaning
1	Ossetian	атр	—
2	Proto-Iranian	*HáHtr̥š	—
3	Proto-Indo-Iranian	*HáHtr̥š	—
4	Proto-Indo-European	h₂eh₁ter-	fire

арт — Etymology, Origin & Word History | Etymology Explorer