Source : Webster's Revised Unabridged Dictionary (1913)

Torpedo-boat destroyer \Tor*pe"do-boat` de*stroy"er\
   A larger, swifter, and more powerful armed type of torpedo
   boat, originally intended principally for the destruction of
   torpedo boats, but later used also as a more formidable
   torpedo boat.

Source : WordNet®

torpedo-boat destroyer
     n : small destroyer that was the forerunner of modern
         destroyers; designed to destroy torpedo boats