A chemical element, in the periodic table Krypton has the symbol Kr and atom number 36. It is one of the so-called noble gases, and was discovered by fractionating liquefied air. The name Krypton is from a Greek word meaning "hidden".
Krypton is the name of the fictional birth planet of Kal-El, better known as Superman. Krypton orbited a red giant star, and was destroyed in an explosion that converted much of its mass into Kryptonite.