A nonspecific term used with various shades of meaning in the technical literature. It should not be used as a synonym for substance, but is generally used in the collective expressions “raw materials” and “materials handling.” The term material balance. in chemical engineering denotes the sum of all the substances entering a reaction and all those that leave it in a given time period. Material also loosely refers to closely associated mixtures, either of natural origin (petroleum, wood, ores) or man-made (glass, cement, composites).See Substance; Engineering Material; Raw Material.