MOLD

also spelled mould, in biology, a conspicuous mass of mycelium (masses of vegetative filaments, or hyphae) and fruiting structures produced by various fungi (division Mycota).Fungi of the genera Aspergillus, Penicillium, and Rhizopus form mold and are associated with food spoilage and plant diseases. also spelled Mould, in manufacturing, a cavity or matrix in which a fluid or plastic substance is shaped into a desired finished product. A molten substance, such as metal, or a plastic substance is poured or forced into a mold and allowed to harden. Molds are made of a wide variety of materials, depending on the application; sand is frequently used for metal casting, hardened steel for molds for plastic materials, and plaster for various purposes. See also investment casting; lost-wax process.