The name of Ireland (in English) or Éire (in Irish)

The etymology of the name Éire is uncertain and various theories have been proposed. There is no doubt but that it is a name of considerable antiquity. It first appears as Ierne in Greek geographical writings, which may be based on sources as early as the 5th century BC. In Ptolemy's map (c AD 150) the name appears as Iouernia; some such form was transliterated into Latin as Iuverna. The standard Latin form, Hibernia, first appears in the works of Caesar, who seems to have confused it with the Latin word hibernus (wintry). Ériu, the Old Irish form of Éire, was current in the earliest Irish literature. The modern English word Ireland derives from the Irish word Éire with the addition of the Germanic word land.

In mythology, Éiruwas one of three divine eponyms for Ireland, together with Banba and Fodla. The idea of Ireland as a heroine reappears as a common motif in later literature in both Irish and English.