Where does “Rabu” come from?

Rabu (Malay) comes from Sanaani Arabic ربوع, from Arabic الأَرْبَعَاء.

Ancestry of “Rabu”, step by step

Step	Language	Word	Meaning
1	Sanaani Arabic	ربوع	—
2	Arabic	الأَرْبَعَاء	—

Rabu — Etymology, Origin & Word History | Etymology Explorer