(n.) One of two circular stones used for grinding grain or other substance.

bale burden burdening burthen cargo charge charging cheese grater comminutor crusher cumber cumbrance deadweight drag duty encumbrance freight granulator grater grinder handicap incubus incumbency kominuter lading levigator load loading masher mill mortar and pestle nutmeg grater onus oppression overload overtaxing overweighting pestle pressure pulverizer quern quernstone rock crusher roller saddling shredder steamroller superincumbency surcharge task tax taxing triturator weight