Irish

From Middle English Irish (12th c.), from Old English *Īrisċ, from Old English Īras (“Irishmen”), from Old Norse Írar, from Old Irish Ériu (modern Irish Éire (“Ireland”)), further origin heavily debated but probably from Proto-Celtic *Φīweriyū (“fat land, fertile”), from Proto-Indo-European *péyh₂wr̥ (“fat, swelling”), from *peyh₂- (“to swell; to be fat”), akin to Ancient Greek πῑ́ειρα (pī́eira, “fertile land”), Sanskrit पीव॑री (pī́varī, “fat”).