Real Dictionary

nitrogen
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
any of the taxonomic groups into which a genus is divided, the members of which are capable of interbreeding: often containing subspecies, varieties, or races. A species is designated in italics by the genus name followed by the specific name, for example
the sum total of the chemical processes that occur in living organisms, resulting in growth, production of energy, elimination of waste material, etc [...]
uncountable noun: Nitrogen is a colourless element that has no smell and is usually found as a gas. It forms about 78% of the earth's atmosphere, and is found in all living things.