colorless, odorless gaseous element, 1794, from French nitrogène, coined 1790 by French chemist Jean Antoine Chaptal (1756-1832), from Greek nitron "sodium carbonate" (see nitro-) + French gène "producing," from Greek -gen "giving birth to" (see -gen). The gas was identified in part by analysis of nitre. An earlier name for it was mephitic air (1772), and Lavoisier called it azote (see azo-). It forms about 78% of the weight of the Earth's atmosphere. Related: Nitrogenic; nitrogenous.