Where does “रात्री” come from?

रात्री (Sanskrit) comes from Proto-Indo-Iranian HráHtriH, from Proto-Indo-European Hréh₁trih₂.

Ancestry of “रात्री”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-Iranian	HráHtriH	—
2	Proto-Indo-European	Hréh₁trih₂	—

रात्री — Etymology, Origin & Word History | Etymology Explorer