Where does “חַמְשָׁא” come from?

חַמְשָׁא (Aramaic) comes from Proto-Semitic ḫamš- — five.

Ancestry of “חַמְשָׁא”, step by step

Step	Language	Word	Meaning
1	Proto-Semitic	ḫamš-	five

חַמְשָׁא — Etymology, Origin & Word History | Etymology Explorer