What does walnut mean in cooking?

walnut means: Originating in Asia, the walnut tree is found inside green pods that turn brown when dry and look woody. (in Cooking Dictionary)

What else does walnut mean?

• One of many deciduous trees in the genus Juglans, Pinnately-composed leaves and fruit with a round sticky husk, which encloses an edible seeds with a hardshell. (in Merlin Dictionary)
• Any of these trees can be used to produce a nut or corrugated seeds. (in Merlin Dictionary)
• These trees’ hard brown wood is used in gunstocks as well as cabinetwork. (in Merlin Dictionary)