Source : Webster's Revised Unabridged Dictionary (1913)

Hyposulphuric \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}.