Where does “Èirinn” come from?

Èirinn (Scottish Gaelic) comes from Old Irish Érinn, from Old Irish Ériu, from Primitive Irish *Īweriū, from Proto-Celtic Φīweryū, from Proto-Indo-European piHweryon-, from Proto-Indo-European peyH- — fat, milk.

Èirinn (Scottish Gaelic): Ireland

Definitions

Ireland

Ancestry of “Èirinn”, step by step

Step	Language	Word	Meaning
1	Old Irish	Érinn	—
2	Old Irish	Ériu	Ireland
3	Primitive Irish	*Īweriū	—
4	Proto-Celtic	Φīweryū	—
5	Proto-Indo-European	piHweryon-	—
6	Proto-Indo-European	peyH-	fat, milk

Words derived from “Èirinn”

Èireannach
ban-Eireannach

Every word from Proto-Indo-European peyH- →Every word from Proto-Indo-European piHweryon- →Every word from Proto-Celtic Φīweryū →