pyrotechnics (pĪˌrōtĕkˈnĭks, pĪˌrə–) [key], technology of making and using fireworks. Gunpowder was used in fireworks by the Chinese as early as the 9th cent., and it was they who brought fireworks to a high stage of development. The use of fireworks for display has spread throughout the world. In many countries fireworks are used to celebrate national holidays, e.g., Independence Day in the United States and Bastille Day in France. Many combustibles and explosives and ingenious combinations of the two have been devised to produce impressive sounds and lights of many colors and to drive wheels and rockets. Fireworks are also widely used as signal devices, e.g., various colored flares and smoke grenades to denote distress or to locate targets in military operations. Powerful flares are also used in combat to illuminate enemy positions.