Source : Webster's Revised Unabridged Dictionary (1913)

Stannous \Stan"nous\ (-n[u^]s), a. (Chem.)
   Pertaining to, or containing, tin; specifically, designating
   those compounds in which the element has a lower valence as
   contrasted with {stannic} compounds.

   {Stannous chloride} (Chem.), a white crystalline substance,
      {SnCl2.(H2O)2}, obtained by dissolving tin in hydrochloric
      acid. It is used as a mordant in dyeing.

Source : WordNet®

stannous
     adj : of or relating to or containing tin [syn: {stannic}]