Hi
Erin,
Here's a quote from "Brewer's Dictionary of Names - People & Places & Things":
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Ireland:
The western island and independent republic of the British Isles has a name that means "EIRE land", the first word here being the Irish name for the country. It may itself mean "western land" from a root word related to Gaelic 'iar' "west", although some sources see it as a blend of Gaelic 'i' "island" and 'iarunn' "iron". The Latin name of
Ireland, 'Hibernia', evolved as a corruption of 'Iverna', itself representing Old Celtic 'Iveriu'. This gave both the poetic name of
Ireland, '
Erin', and the name for the land in other Celtic languages, such as Welsh 'Iwerddon', Breton 'Iwerzhon' and Cornish 'Ywerdhon'.
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In an Online Etymology Dictionary I found another theory:
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Irish:
c.1205, Irisce, from stem of O.E. Iras "inhabitant of
Ireland," from O.N. irar, ult. from O.Ir. Eriu "
Erin." Meaning "temper, passion" is 1834, Amer.Eng. (first attested in writings of
Davy Crockett), from the legendary pugnacity of Irish people. Irish-American is from 1832; Irish coffee is from 1950. Wild Irish (1399) originally were those not under English rule; Black Irish in ref. to those of Mediterranean appearance is from 1888.
http://www.etymonline.com/index.php?search=erin&searchmode=none
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The meaning "peace" you've read about is probably a confusion of
Erin and
Eireen, which is an Irish variant spelling for
Irene (see link).
/
Satu
http://www.nordicnames.de/