Nicker nut

from WordNet (r) 3.0 (2006)

nicker nut
    n 1: hard shiny grey seed of a bonduc tree; used for making e.g.
         jewelry [syn: {bonduc nut}, {nicker nut}, {nicker seed}]

from The Collaborative International Dictionary of English v.0.48

Nicker nut \Nick"er nut`\
   A rounded seed, rather smaller than a nutmeg, having a hard
   smooth shell, and a yellowish or bluish color. The seeds grow
   in the prickly pods of tropical, woody climbers of the genus
   {Caesalpinia}. {Caesalpinia Bonduc} has yellowish seeds;
   {Caesalpinia Bonducella}, bluish gray. [Spelt also {neckar
   nut}, {nickar nut}.]
   [1913 Webster]