The Collaborative International Dictionary of English v.0.48:

Fallow deer \Fal"low deer`\ [So called from its fallow or pale
   yellow color.] (Zool.)
   A European species of deer (Cervus dama), much smaller than
   the red deer. In summer both sexes are spotted with white. It
   is common in England, where it is often domesticated in the
   parks.
   [1913 Webster]

WordNet (r) 3.0 (2006):

fallow deer
    n 1: small Eurasian deer [syn: fallow deer, Dama dama]