Where does “acaio” come from?

acaio (Portuguese) comes from English Achaius, from Old Irish Eochaid, from Primitive Irish ᚓᚊᚑᚇᚇᚔ, from Proto-Celtic ekʷos, from Proto-Indo-European h₁éḱwos, from Proto-Indo-European h₁oh₁ḱu- — swift.

Ancestry of “acaio”, step by step

StepLanguageWordMeaning
1EnglishAchaiusof historical usage only
2Old IrishEochaid—
3Primitive Irishᚓᚊᚑᚇᚇᚔ—
4Proto-Celticekʷoshorse
5Proto-Indo-Europeanh₁éḱwosstallion, horse
6Proto-Indo-Europeanh₁oh₁ḱu-swift
Every word from Proto-Indo-European h₁oh₁ḱu- →Every word from Proto-Indo-European h₁éḱwos →Every word from Proto-Celtic ekʷos →