An Etymological Dictionary of the German Language/Annotated/Flötz

by Friedrich Kluge

Flötz, neuter, older Fletze, neuter, ‘vein of ore,’ from Middle High German vlętze, neuter, ‘threshing-floor, vestibule, stratum,’ Old High German flęzzi; compare Anglo-Saxon flętt, ‘floor of the hall,’ Old Icelandic flet, ‘room, hall’; akin to the Old Icelandic adjective flatr, Old High German flaȥ, ‘flat, wide, level,’ mentioned under Fladen and flach.