In Irish mythology,
Ériu (Irish pronunciation: [ˈeːrʲu]; modern Irish Éire), daughter of Ernmas of the Tuatha Dé Danann, was the eponymous matron goddess of Ireland. Her husband was Mac Gréine (‘Son of the Sun’).[1]
The English name for Ireland comes from the name Ériu and the Germanic (Old Norse or Old English) word land.
The fact that Ériu is represented as goddess of Ireland, she is often interpreted as a modern day personification of Ireland, although since the name "Ériu" is the older Irish form of the word Ireland, her modern name is often modified to "Éire" or "Erin" to suit a modern form.
The University of Wales' reconstructed Proto-Celtic lexicon gives *Φīwerjon- (nominative singular Φīwerjō) as the Proto-Celtic etymology of this name.[4] This
Celtic form implies Proto-Indo-European *piHwerjon-, likely related to the adjectival stem *
piHwer- "fat" (cf. Sanskrit pīvan, f. pīvarī and by-form pīvara,
"fat, full, abounding") hence meaning "fat land" or "land of abundance", applied at an early date to the island of Ireland. The Proto-Celtic form became *īweriū [5] in Q-Celtic (Proto-Goidelic). ...