Where does “μερίς” come from?

μερίς (Ancient Greek) comes from Ancient Greek μέρος, from Proto-Hellenic *(h)méros.

μερίς (Ancient Greek): part; a part

Definitions

Step	Language	Word	Meaning
1	Ancient Greek	μέρος	part, component, region; share, portion; one's...
2	Proto-Hellenic	*(h)méros	—

μερίς — Etymology, Origin & Word History | Etymology Explorer