Etymology

From Proto-Hellenic *íkkʷos, from Proto-Indo-European *h₁éḱwos, from *h₁oh₁ḱu- ‎(“swift”). Unexplained is (h)i for e. Cognates include Sanskrit अश्व ‎(áśva), Latin equus, Gaulish epos, Old Armenian էշ ‎(ēš, “donkey”) and Old English eoh.