I've read that it comes from the ancient name for
Ireland meaning peace. I believe this name for
Ireland was from the Celtic language. The other meaning for
Erin meaning western Island or
Ireland is Gaelic. I'm not saying that this is correct for sure but it's what I read.
I've bought different things with my name and it's meaning on it and sometimes it says
Erin means peace and other times
Ireland. : ) Who knows. I wish I knew someone who speaks Gaelic or Celtic.