An Etymological Dictionary of the German Language/Annotated/Aar
Aar, masculine, from the equivalent Middle High German ar, Old High German aro, masculine, ‘eagle’; a primary Teutonic word, which has also cognates outside the Teutonic group. Compare Gothic ara, Old Icelandic are, masculine, ‘eagle'; further Old Icelandic ǫrn, Old High German, Middle High German arn (to which is allied Modern High German Arnold, Old High German Aranolt, original sense ‘eagle-guardian'), Anglo-Saxon earn, ‘eagle,’ Dutch arend, ‘eagle'; primarily cognate with Old Slovenian orĭlŭ, Lithuanian erélis, ‘eagle,’ Greek ὄρνις, ‘bird,’ Cornish and Breton er. Welsh eryr, ‘eagle.’ See Adler.