Where does “Éris” come from?

Éris (Portuguese) comes from Ancient Greek ἔρις, from Proto-Indo-European h₁er- — earth.

Ancestry of “Éris”, step by step

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

Éris — Etymology, Origin & Word History | Etymology Explorer