An Etymological Dictionary of the German Language/Annotated/Quader

Quader, masculine, ‘squared stone,’ from the equivalent Middle High German quâder, masculine and neuter, which is based on Latin quā̆drum, ‘square,’ or rather quā̆drus (scil. lapis), ‘square stone.’ Compare Italian quadro, ‘square,’ Provençal caire, ‘square stone’ (Italian quadrello, French carreau).