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.]

WordNet (r) 3.0 (2006):

topi
    n 1: a lightweight hat worn in tropical countries for protection
         from the sun [syn: pith hat, pith helmet, sun helmet,
         topee, topi]
    2: a large South African antelope; considered the swiftest
       hoofed mammal [syn: sassaby, topi, Damaliscus lunatus]