Hy`po*sul*phur"ic (?), a. [Pref. hypo- + sulphuric.] (Chem.) Pertaining to, or containing, sulphur in a lower state of oxidation than in the sulphuric compounds; as, hyposulphuric acid.

Hyposulphuric acid, an acid, H₂S₂O₆, obtained by the action of manganese dioxide on sulphur dioxide, and known only in a watery solution and in its salts; -- called also dithionic acid. See Dithionic.