waterbok

from The Collaborative International Dictionary of English v.0.48

Water buck \Wa"ter buck`\ (Zool.)
   A large, heavy antelope ({Kobus ellipsiprymnus}) native of
   Central Africa. It frequents the banks of rivers and is a
   good swimmer. It has a white ring around the rump. Called
   also {photomok}, {water antelope}, and {waterbok}.
   [1913 Webster]

   Note: The name is also applied to other related species, as
         the leche ({Kobus leche}), which has similar habits.
         [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Waterbok \Wa"ter*bok`\, n. [D.] (Zool.)
   A water buck.
   [1913 Webster]