Real Dictionary

nitrogen in American English
a colorless, tasteless, odorless, gaseous chemical element forming nearly four fifths of the atmosphere: it is a component of all proteins and nucleic acids: symbol, N; at. no., 7
noun: 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, esp. in proteins: used chiefly in the manufacture of ammonia, nitric acid, cyanide,

nitrogen in British English
noun: a colourless odourless relatively unreactive gaseous element that forms 78 per cent (by volume) of the air, occurs in many compounds, and is an essential constituent of proteins and nucleic acids: used in the manufacture of ammonia and other chemicals and