corrosion (n.)

c. 1400, corrosioun, from Old French corrosion and directly from Latin corrosionem (nominative corrosio), noun of action from past-participle stem of corrodere "to gnaw to bits, wear away," from assimilated form of com-, here probably an intensive prefix (see com-), + rodere "to gnaw" (possibly from an extended form of PIE root *red- "to scrape, scratch, gnaw").