An Etymological Dictionary of the German Language/Annotated/Mohn
Mohn, masculine, from the equivalent late Middle High German mân, earlier mâhen, masculine, ‘poppy’; Old High German *mâhan is wanting, for which Old High German mâgo, Middle High German mâge, masculine, ‘poppy,’ with a change of h to g (see fragen and Zähre), is used (compare Gothic þahan with Old High German dagên, Latin tacere); to this Upper German mâgsame (Alsatian mâss), ‘poppy,’ is allied. It corresponds to Old Swedish valmughi, Swedish vallmo, ‘poppy.’ The word points to pre-Teutonic mêkon-, besides which the form mâkon- is presupposed by Greek μήκων (Doric μᾶκων), Old Slovenian makŭ, ‘poppy.’ These correspondences, however, do not necessarily imply that the cognates are of genuine Aryan origin (compare Hanf). For Old High German mâgo a form popig (English poppy) was used in Anglo-Saxon, based on Latin papaver.