Where does “ῥαχῖτις” come from?

ῥαχῖτις (Koine Greek) comes from Ancient Greek -ῖτις — female equivalent of -ίτης.

Ancestry of “ῥαχῖτις”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	-ῖτις	female equivalent of -ίτης

ῥαχῖτις — Etymology, Origin & Word History | Etymology Explorer