An Etymological Dictionary of the German Language/Annotated/oder

by Friedrich Kluge

oder, conjunction, from the equivalent Middle High German oder, Old High German odar, ‘or, else’; the Old High German and Middle High German ordinary form are without r; Old High German odo, earlier ëddo, Middle High German ode, od. This abnormal r is, according to some, a comparative suffix; according to others it is simply an suffix due to the influence of Old High German wëdar, Middle High German wëder, ‘neither.’ Old High German ëddo, ëdo, correspond further to Gothic aíþþau, ‘or,’ which is a compound of Gothic iþ, ‘and’ (Latin et), and þau, ‘or.’ English or has no connection with this word, since it originated in Anglo-Saxon âhwœþer; Gothic aíþþau is Anglo-Saxon oþþe and ëþþa, ‘or,’ which became obsolete ar an early period.