n.
n. [ OE. mullen to pulverize, bruise; cf. Icel. mylja; prob. akin to E. mold soil. See Mold soil, and cf. Mull dirt. ] A stone or thick lump of glass, or kind of pestle, flat at the bottom, used for grinding pigments or drugs, etc., upon a slab of similar material. [ 1913 Webster ]