资料来源 : Webster's Revised Unabridged Dictionary (1913)

Ferric \Fer"ric\, a. [L. ferrum iron: cf. F. ferrique. See
   {Ferrous}.]
   Pertaining to, derived from, or containing iron. Specifically
   (Chem.), denoting those compounds in which iron has a higher
   valence than in the ferrous compounds; as, ferric oxide;
   ferric acid.

   {Ferric acid} (Chem.), an acid, {H2FeO4}, which is not known
      in the free state, but forms definite salts, analogous to
      the chromates and sulphates.

   {Ferric oxide} (Chem.), sesquioxide of iron, {Fe2O3};
      hematite. See {Hematite}.

资料来源 : WordNet®

ferric oxide
     n : a red oxide of iron