The Collaborative International Dictionary of English v.0.48:

Pithecoid \Pith"e*coid\, a. [Gr. ? an ape + -oid.] (Zool.)
   1. Of or pertaining to the genus Pithecia, or subfamily
      Pithecin[ae], which includes the saki, ouakari, and
      other allied South American monkeys.
      [1913 Webster]

   2. Of or pertaining to the anthropoid apes in particular, or
      to the higher apes of the Old World, collectively.
      [1913 Webster]