Source : Webster's Revised Unabridged Dictionary (1913)

Pronghorn \Prong"horn`\, n. (Zo["o]l.)
   An American antelope ({Antilocapra Americana}), native of the
   plain near the Rocky Mountains. The upper parts are mostly
   yellowish brown; the under parts, the sides of the head and
   throat, and the buttocks, are white. The horny sheath of the
   horns is shed annually. Called also {cabr['e]e}, {cabut},
   {prongbuck}, and {pronghorned antelope}.

Source : WordNet®

pronghorn
     n : fleet antelope-like ruminant of western North American
         plains with small branched horns [syn: {prongbuck}, {pronghorn
         antelope}, {American antelope}, {Antilocapra americana}]