Krypton
Krypton (krip"ton) , noun
[New Latin, from Greek krypto`n, neut. of krypto`s hidden.]
(Chemistry) An inert gaseous element of the argon (noble gas) group, of atomic number 36, occurring in air to the extent of about one volume in a million. It was discovered by Ramsay and Travers in 1898. Boiling point, -152.3° C.; melting point, -156.6° C.; symbol, Kr; atomic weight, 83.8.