1) Iron with a carbon content that exceeds the solubility limit of carbon in austenite (approximately 1.8%) at the eutectic temperature. Cast Irons typically contain 1.8-4.5% carbon, plus silicon, sulfur, and phosphorus; they may also have other alloying elements such as chromium, manganese, nickel, and vanadium. 2) A generic term for a large family of cast ferrous alloys like gray cast iron, white cast iron, malleable cast iron and ductile cast iron. Sometimes the word "cast" is left out, resulting in "gray iron," "white iron," "malleable iron," and "ductile iron," respectively.