An Etymological Dictionary of the German Language/platt
platt, adj., ‘flat, level, dull, downright’; in MidHG., only MidG. blatefuoȥ and platehuof, ‘flat foot, sole of the foot,’ are recorded. It is most closely connected with Du. (LG.) plat, ‘plat,’ which, like E. dial. plat-footed (i.e. flat-footed), is derived from Rom., Fr. plat, Ital. piatto. Their origin is ascribed to Gr. πλατύς. To this plätten (Du. pletten), ‘to flatten, iron (clothes),’ is allied, as well as Platte, f., ‘flat, dish’ (MidHG. blate, plate, signify only ‘covering for the breast, baldness’), formed from Du. plat, ‘flat,’ Fr. plat, E. plate.