Source : Webster's Revised Unabridged Dictionary (1913)

Bloodhound \Blood"hound`\, n.
   A breed of large and powerful dogs, with long, smooth, and
   pendulous ears, and remarkable for acuteness of smell. It is
   employed to recover game or prey which has escaped wounded
   from a hunter, and for tracking criminals. Formerly it was
   used for pursuing runaway slaves. Other varieties of dog are
   often used for the same purpose and go by the same name. The
   Cuban bloodhound is said to be a variety of the mastiff.

Source : WordNet®

bloodhound
     n : a breed of large powerful hound of European origin having
         very acute smell and used in tracking [syn: {sleuthhound}]