Where does “Ratri” come from?

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

Ancestry of “Ratri”, step by step

Step	Language	Word	Meaning
1	Sanskrit	रात्रि	night
2	Sanskrit	रात्री	—
3	Proto-Indo-Iranian	HráHtriH	—
4	Proto-Indo-European	Hréh₁trih₂	—

Ratri — Etymology, Origin & Word History | Etymology Explorer