Nitrous \Ni"trous\, a. [L. nitrosus full of natron: cf. F. nitreux. See Niter.]

1. Of, pertaining to, or containing, niter; of the quality of niter, or resembling it.

2. (Chem.) Of, pertaining to, or designating, any one of those compounds in which nitrogen has a relatively lower valence as contrasted with nitric compounds.

Nitrous acid (Chem.), a hypothetical acid of nitrogen HNO2, not known in the free state, but forming a well known series of salts, viz., the nitrites.

Nitrous oxide. See Laughing gas.

Source: Webster's Revised Unabridged Dictionary (1913)