Source : Webster's Revised Unabridged Dictionary (1913)

Hypochlorous \Hy`po*chlo"rous\, a. [Pref. hypo- + chlorous.]
   (Chem.)
   Pertaining to, or derived from, chlorine having a valence
   lower than in chlorous compounds.

   {Hypochlorous acid} (Chem.), an acid derived from chlorine,
      not known in a pure state, but forming various salts,
      called hypochlorites.

Source : WordNet®

hypochlorous acid
     n : a weak unstable acid known only in solution and in its
         salts; used as a bleaching agent and as an oxidizing
         agent