The Collaborative International Dictionary of English v.0.48:

Topi \To"pi\, n.
   An antelope (Damaliscus corrigum jimela) having a glossy
   purplish brown coat. It is related to the blesbok and is
   native of East Africa. Also, any of various related varieties
   of other districts south of the Sahara.
   [Webster 1913 Suppl.]