Any of numerous substances that can be shaped and molded when subjected to heat or pressure. Plastics are easily shaped because they consist of long-chain molecules known as polymers, which do not break apart when flexed. Plastics are usually artificial resins but can also be natural substances, as in certain cellular derivatives and shellac. Plastics can be pressed into thin layers, formed into objects, or drawn into fibers for use in textiles. Most do not conduct electricity well, are low in density, and are often very tough. Polyvinyl chloride, methyl methacrylate, and polystyrene are plastics. See more at
thermoplastic, thermosetting. Capable of being molded or formed into a shape.