Where does “ခုနစ်” come from?

ခုနစ် (Burmese) comes from Proto-Sino-Tibetan s-ni-s — seven.

ခုနစ် (Burmese): seven

Definitions

Step	Language	Word	Meaning
1	Proto-Sino-Tibetan	s-ni-s	seven

ခုနစ် — Etymology, Origin & Word History | Etymology Explorer