composite material or composite, any material made from at least two discrete substances, such as concrete. Many materials are produced as composites, such as the fiberglass-reinforced plastics used for automobile bodies and boat hulls, but the term usually is used to describe any of various modern industrially manufactured composites, such as carbon fiber–reinforced plastics. Composite materials allow a blending of properties of the separate components. Carbon fiber–reinforced plastics combine the high strength and stiffness of the fiber with the low weight and resistance to fracture of the polymeric matrix. Glass, wood, and other kinds of fibers are also used, and the fibers may be layered or woven. Other modern composites include wood fiber or chunks in a concrete matrix and silicon carbide, a ceramic, in a titanium matrix.