Real Dictionary

krypton
uncountable noun: Krypton is an element that is found in the air in the form of a gas. It is used in fluorescent lights and lasers.

krypton in American English
a rare, gaseous chemical element, one of the noble gases, present in very small quantities in air: basically inert, it reacts with fluorine and some other elements under special conditions: symbol, Kr; at. no., 36
noun: an inert, monatomic gaseous element, present in very small amounts in the atmosphere: used in high-power, tungsten-filament light bulbs: at. wt.: 83.80; at. no.: 36

krypton in British English
noun: colourless odourless element of the rare gas group, occurring in trace amounts in air and used in fluorescent lights and lasers. Symbol: Kr; atomic no: 36; atomic wt: 83.80; valency: 0; density: 3.733 kg/ m3; melting pt: –157.37° C; boiling pt: –153.23±0.