Ireland or Erin is Celtic; from Eri or Iar (western). Lloyd (State Worthies, article "Grandison"), with a
gravity which cannot but excite laughter, says the island is called the land of Ire because of the broils
there, which have extended over four hundred years. Wormius derives the word from the Runic Yr, a
bow. (See below.)
Ireland.
Called by the natives "Erin," i.e. Eri-innis, or Iar-innis (west island).
By the Welsh "Yver-den" (west valley).


Tricky, that, because the Welsh language does not contain the letter V!

The actual current name for Ireland in Welsh is Iwerddon, pronounced (roughly) i-wear-thon.