Hy′po‐sul″phur‐ous (?), a. [Pref. hypo- + sulphurous.] (Chem.) Pertaining to, or containing, sulphur, all, or a part, in a low state of oxidation.
Hyposulphurous acid. (a) Thiosulphuric acid. (b) An acid, H2SO2, obtained by the reduction of sulphurous acid. It is not obtained in the free state, but in an orange-yellow water solution, which is a strong reducing and bleaching agent. Called also hydrosulphurous acid.