Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
material, materiel (nn.)
Material, pronounced muh-TEER-ee-uhl, is “the stuff of which something may be made,” and it has specialized senses too, including “cloth,” “a performer’s script or act,” and “the equipment and tools needed for doing or making something.” Materiel, pronounced either muh-TEER-ee-EL or as a homophone of material, is “the tools and equipment of an army or some other enterprise.”
