Fire

Production of light and heat by the combustion of substances; from ancient times regarded as an elemental substance and not understood until the development of the modern theory of combustion and the nature of the physical forces of light and heat. It is now restricted to the combustion of solid, liquid, or gaseous materials in which light and heat are produced. See COMBUSTION, FIRE WORSHIP, FLAME, FUEL, HEAT, LIGHT, and MATCHES.