a. Covered with defensive plates of metal, as a ship of war; steel-clad. [ 1913 Webster ]
This day will be launched . . . the first armor-plated steam frigate in the possession of Great Britain. Times (Dec. 29, 1860). [ 1913 Webster ]
adj. 1. 1 protected with a covering of armor. Syn. -- steel-plated. [ WordNet 1.5 ]