[‚dī′meth·əl‚ȯl·yu̇′rē·ə] (organic chemistry) CO(NHCH2OH)2 Colorless crystals melting at 126°C, soluble in water; used to increase fire resistance and hardness of wood, and in textiles to prevent wrinkles. Also known as 1,3-bis-hydroxymethylurea; DMU.