black walnut

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An eastern North American tree (Juglans nigra) having dark brown wood and a deeply furrowed nut enclosed in a globose aromatic husk.
• noun The wood of this tree, used especially for veneer, cabinets, furniture, and gunstocks.
• noun The nut of this tree, having an edible kernel.

from The Century Dictionary.

• noun See walnut.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun North American walnut tree with hard dark wood and edible nut
• noun American walnut having a very hard and thick woody shell