(Chem; Symb: N) A colorless, odorless, tasteless, diatomic gaseous element that forms approx 78% of the air in the earth's atmosphere, bp -185. 80C, fp -209. 80C. Nitrogen is extremely inert, but it is an essential element in all plant and animal life and is important in the production of nitric acid, ammonia, cyanides, and as a cryogenic when liquefied. Note: Calcium, magnesium, and aluminum will "burn" in a nitrogen atmosphere without oxygen