The Collaborative International Dictionary of English v.0.48:

Tschego \Tsche"go\, n. [From a native name.] (Zool.)
   A West African anthropoid ape allied to the gorilla and
   chimpanzee, and by some considered only a variety of the
   chimpanzee. It is noted for building large, umbrella-shaped
   nests in trees. Called also tscheigo, tschiego,
   nschego, nscheigo.
   [1913 Webster]