The Collaborative International Dictionary of English v.0.48:

Coquilla nut \Co*quil"la nut\ [Pg. coquilho, Sp. coquillo, dim.
   of coco a cocoanut.] (Bot.)
   The fruit of a Brazilian tree (Attalea funifera of
   Martius.).
   [1913 Webster]

   Note: Its shell is hazel-brown in color, very hard and close
         in texture, and much used by turners in forming
         ornamental articles, such as knobs for umbrella
         handles.
         [1913 Webster]

WordNet (r) 3.0 (2006):

coquilla nut
    n 1: nut having a hard hazel-brown shell used like vegetable
         ivory