Erin is a personal name taken from the Hiberno-English word for Ireland, originating from the Irish word "Éirinn". "Éirinn" is the dative case of the Irish word for Ireland, "Éire", genitive "Éireann", the dative being used in prepositional phrases such as "go hÉirinn" "to Ireland", "in Éirinn" "in Ireland", "ó Éirinn" "from Ireland".
The dative has replaced the nominative in a few regional Irish dialects (particularly Galway-Connemara and Waterford).
