An Etymological Dictionary of the German Language/Annotated/gemein
gemein, adjective, ‘common, public; mean, vulgar,’ from Middle High German gemeine, Old High German gimeini, ‘belonging to one another, in common, universal, belonging to the great body’; an adjective common to Teutonic; compare Gothic gamains, ‘in common, joint, general, unholy,’ Anglo-Saxon gemœ̂ne, English mean, Dutch gemeen. The common Teutonic ga-maini-s is primitively allied to the equivalent Latin com-mûnis (for com-moini-s); compare Latin ûnus with Gothic ains, Aryan oino-s. Since ‘in common’ is the primary meaning of the class, Meineid (which see) cannot be very closely allied to its Old Teutonic cognates.