An Etymological Dictionary of the German Language/Annotated/platt
platt, adjective, ‘flat, level, dull, downright’; in Middle High German, only Middle German blatefuoȥ and platehuof, ‘flat foot, sole of the foot,’ are recorded. It is most closely connected with Dutch (Low German) plat, ‘plat,’ which, like English dialectic plat-footed (i.e. flat-footed), is derived from Romance, French plat, Italian piatto. Their origin is ascribed to Greek πλατύς. To this plätten (Dutch pletten), ‘to flatten, iron (clothes),’ is allied, as well as Platte, feminine, ‘flat, dish’ (Middle High German blate, plate, signify only ‘covering for the breast, baldness’), formed from Dutch plat, ‘flat,’ French plat, English plate.