nitrogen

noun

Etymology: Borrowed from French nitrogène (coined by French chemist and physician Jean-Antoine Chaptal in 1790). By surface analysis, nitro- + -gen. See also niter.

1. The chemical element (symbol N) with an atomic number of 7 and atomic weight of 14.0067. It is a colorless and odorless gas.

   “Holonyms: dinitrogen, N₂, nitrogen (loose sense)”

   “By molar fraction, nitric oxide contains equal parts nitrogen and oxygen.”

2. Molecular nitrogen (diatomic nitrogen), N₂, a colorless, odorless gas at room temperature, which constitutes most of air (78% of it).

   “Meronyms: nitrogen (strict sense), N”

   “The air you breathe is mostly nitrogen.”

3. A specific nitrogen atom within a chemical formula, or a specific isotope of nitrogen.

   “The two nitrogens are located next to one another on the ring.”