At its core, the word “composite” means a “mixture” or “compound.” Today, engineers use this word to refer to a material consisting of two or more parts. The properties of a composite differ quantitatively and qualitatively from the properties of each of its constituent materials. Despite the variety of compositions, most of the composite materials have two fundamental parts: the reinforced filler, which is responsible for the desired mechanical properties, and the matrix, which binds the reinforcing elements.