The Collaborative International Dictionary of English v.0.48:

borzoi \borzoi\ n. [Russian.]
   tall, slender fast-moving dog breed; called also Russian
   wolfhound.

   Syn: Russian wolfhound.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Russian wolfhound
    n 1: tall fast-moving dog breed [syn: borzoi, Russian
         wolfhound]