Krypton is a chemical element with the atomic number 36 and the symbol Kr. It is a noble gas that is odorless, colorless, and tasteless. Krypton is found in trace amounts in the Earth's atmosphere and is used in certain types of lighting, such as neon signs and fluorescent bulbs. It is also used in some lasers and as an indicator gas in nuclear reactors. Krypton gets its name from the Greek word "kryptos," which means hidden or secret, due to the fact that it was discovered as a trace component in liquid air that was believed to only contain nitrogen and oxygen at the time.