nitrous, a. [L. nitrosus full of natron: cf. F. nitreux. See Niter.].
Of, pertaining to, or containing, niter; of the quality of niter, or resembling it. [1913 Webster]
Of, pertaining to, or designating, any one of those compounds in which nitrogen has a relatively lower valence as contrasted with nitric compounds. [1913 Webster]
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. --