What is Nitrogen?

Nitrogen definition and meaning on Dictionary terms:
noun Chemistry.
a colorless, odorless, gaseous element that constitutes about four-fifths of the volume of the atmosphere and is present in combined form in animal and vegetable tissues, especially in proteins: used chiefly in the manufacture of ammonia, nitric acid, cyanide, explosives, fertilizer, dyes, as a cooling agent, etc. Symbol: N; atomic weight: 14.0067; atomic number: 7; density: 1.2506 g/l at 0