The Collaborative International Dictionary of English v.0.48:

Deerhound \Deer"hound`\, n. (Zool.)
   One of a large and fleet breed of hounds used in hunting
   deer; a staghound.
   [1913 Webster]

WordNet (r) 3.0 (2006):

deerhound
    n 1: very large and tall rough-coated dog bred for hunting deer;
         known as the royal dog of Scotland [syn: Scottish
         deerhound, deerhound]