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.

• A large dog. It is a scenthound famed for its ability to follow a scent many days old, over vast distances. This dog is often used as a police dog to track missing people, fleeing suspects, or escaped prisoners.
  
• This breed of dog.
  
• A detective or other skilled at finding people or clues.