[{"Bold_text": "noun", "List Items": ["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.:N;:14.0067;:7;density:1.2506 grams/liter at 0°C and 760 millimeters pressure."]}]