Where does “Pohjois-Irlanti” come from?

Pohjois-Irlanti (Finnish) comes from Finnish Irlanti, from Swedish Irland, from Old Norse Írland, from Old Norse Írar, from Old Irish Ériu, from Primitive Irish *Īweriū, from Proto-Celtic Φīweryū, from Proto-Indo-European piHweryon- — fat, milk.

Ancestry of “Pohjois-Irlanti”, step by step

Pohjois-Irlanti traces back through two separate lines of ancestry.

via Finnish Irlanti

Step	Language	Word	Meaning
1	Finnish	Irlanti	the Irish language
2	Swedish	Irland	—
3	Old Norse	Írland	—
4	Old Norse	Írar	Irishmen
5	Old Irish	Ériu	Ireland
6	Primitive Irish	*Īweriū	—
7	Proto-Celtic	Φīweryū	—
8	Proto-Indo-European	piHweryon-	—
9	Proto-Indo-European	peyH-	fat, milk

via Finnish pohjoinen

Step	Language	Word	Meaning
1	Finnish	pohjoinen	north; northern
2	Finnish	-inen	-like, -ous, -y; -en; Creates adjectives from...
3	Finnish	-uus	Forms nouns from adjectives, expressing a quality
4	Proto-Finnic	-uc	-ness, -hood

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