Where does “Éireannachas” come from?
Éireannachas (Irish) comes from Irish Éireannach, from Old Irish Érennach, from Old Irish Ériu, from Primitive Irish *Īweriū, from Proto-Celtic Φīweryū, from Proto-Indo-European piHweryon-, from Proto-Indo-European peyH- — fat, milk.
Éireannachas (Irish): Irish characteristic
Ancestry of “Éireannachas”, step by step