The Collaborative International Dictionary of English v.0.48:

Corrosion \Cor*ro"sion\ (k?r-r?"zh?n), n. [LL. corrosio: cf. F.
   corrosion. See Corrode.]
   The action or effect of corrosive agents, or the process of
   corrosive change; as, the rusting of iron is a variety of
   corrosion.
   [1913 Webster]

         Corrosion is a particular species of dissolution of
         bodies, either by an acid or a saline menstruum. --John
                                                  Quincy.
   [1913 Webster]

WordNet (r) 3.0 (2006):

corrosion
    n 1: a state of deterioration in metals caused by oxidation or
         chemical action
    2: erosion by chemical action [syn: corrosion, corroding,
       erosion]