walnut

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

• noun Any of several deciduous trees of the genus Juglans, having pinnately compound leaves and fruits with a rounded sticky husk that encloses an edible seed with a hard shell.
• noun The nut or corrugated seed of any of these trees.
• noun The hard, dark brown wood of any of these trees, used for gunstocks and in cabinetwork.

from The Century Dictionary.

• noun The fruit of the nut-bearing tree Juglans regia; also, the tree itself, or its wood.
• noun In the United States, frequently, same as black walnut and rock-walnut (the fruit, the tree, or its wood). See below.
• noun In parts of New York, New England, and some other lo calities, same as hickory-nut or hickory. This is sometimes distinguished as shagbark or shell-bark walnut.
• In the West Indies, a name often applied to the angelin or cabbage-tree, Vouacapoua Americana, from its resemblance in leaf and fruit to the English walnut. See cabbage-tree, 2, and Andira.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) The fruit or nut of any tree of the genus Juglans; also, the tree, and its timber. The seven or eight known species are all natives of the north temperate zone.
• noun a tree (Juglans fraxinifolia), native in Transcaucasia.
• noun a North American tree (Juglans nigra) valuable for its purplish brown wood, which is extensively used in cabinetwork and for gunstocks. The nuts are thick-shelled, and nearly globular.
• noun a tree (Juglans regia), native of Asia from the Caucasus to Japan, valuable for its timber and for its excellent nuts, which are also called Madeira nuts.
• noun a deep warm brown color, like that of the heartwood of the black walnut.
• noun oil extracted from walnut meats. It is used in cooking, making soap, etc.
• noun a North American tree (Juglans cinerea), bearing long, oval, thick-shelled, oily nuts, commonly called butternuts. See Butternut.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A hardwood tree of the genus Juglans.
• noun A nut of the walnut tree.
• noun Wood of the walnut tree.
• noun Dark brown colour, the colour of walnut wood.
• adjective Having a dark brown colour, the colour of walnut wood.

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

• noun nut of any of various walnut trees having a wrinkled two-lobed seed with a hard shell
• noun any of various trees of the genus Juglans
• noun hard dark-brown wood of any of various walnut trees; used especially for furniture and paneling