Princeton's WordNet

1. mockernut, mockernut hickory, black hickory, white-heart hickory, big-bud hickory, Carya tomentosa(noun)

   smooth-barked North American hickory with 7 to 9 leaflets bearing a hard-shelled edible nut

2. pignut, pignut hickory, brown hickory, black hickory, Carya glabra(noun)

   an American hickory tree having bitter nuts

3. black walnut, black walnut tree, black hickory, Juglans nigra(noun)

   North American walnut tree with hard dark wood and edible nut