adjective
(now historical) Pertaining to or composed of nitre; having the properties of nitre, bitter.
(chemistry) Of, relating to, or derived from nitrogen, especially in which the valence of the nitrogen is lower than that of a corresponding nitric species.
(chemistry) Of or relating to nitrous acid or its derivatives.
(mycology, biology) Having a sharp odor like ammonia or nitric acid.
noun
(dentistry, automotive, informal) Nitrous oxide.
(automotive, informal) The system in some racing vehicles which pumps nitrous oxide into the engine to improve performance.