Muller

n. [Prov. Eng. mull, to rub, squeeze, or bruise. Cf. O. Fr. mouleur, mouleur, a grinder; N. Fr. molette, a grindstone for colors, from Lat. molere, to grind; O. Fr. moulir, moulre, molre, moldre, N. Fr. moudre, Pr. molre, Sp. moler, Lat. molaris, a mill-stone, i. q. molaris lapis, from molaris, belonging to a mill or to grinding, from mola, a mill, from molere, to grind.] A sort of pestle of stone or glass, flat at the bottom, used for grinding pigments upon a slab of similar material.