The Collaborative International Dictionary of English v.0.48:

Roebuck \Roe"buck`\, n. [1st roe + buck.] (Zool.)
   A small European and Asiatic deer (Capreolus capraea)
   having erect, cylindrical, branched antlers, forked at the
   summit. This, the smallest European deer, is very nimble and
   graceful. It always prefers a mountainous country, or high
   grounds.
   [1913 Webster]

WordNet (r) 3.0 (2006):

roebuck
    n 1: male roe deer