Where does “Eris” come from?

Eris comes from Ancient Greek Ἔρις, from Ancient Greek ἔρις, ultimately from Proto-Indo-European h₁er-.

Ancestry of “Eris”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	ἔρις	strife, quarrel; contention, rivalry; political...
2	Proto-Indo-European	h₁er-	earth

Eris — Etymology, Origin & Word History | Etymology Explorer