ETYM Old Eng. tree, tre, treo, AS. treó, treów, tree, wood.
1. A figure that branches from a single root; SYN. tree diagram.
2. A tall perennial woody plant having a main trunk and branches forming a distinct elevated crown; includes both gymnosperms and angiosperms.
Perennial plant with a woody stem, usually a single stem or “trunk”, made up of wood and protected by an outer layer of bark. It absorbs water through a root system. There is no clear dividing line between shrubs and trees, but sometimes a minimum achievable height of 6 m/20 ft is used to define a tree.
A treelike form has evolved independently many times in different groups of plants. Among the angiosperms, or flowering plants, most trees are dicotyledons. This group includes trees such as oak, beech, ash, chestnut, lime, and maple, and they are often referred to as broad-leaved trees because their leaves are broader than those of conifers, such as pine and spruce. In temperate regions angiosperm trees are mostly deciduous (that is, they lose their leaves in winter), but in the tropics most angiosperm trees are evergreen. There are fewer trees among the monocotyledons, but the palms and bamboos (some of which are treelike) belong to this group. The gymnosperms include many trees and they are classified into four orders: Cycadales (including cycads and sago palms), Coniferales (the conifers), Ginkgoales (including only one living species, the ginkgo, or maidenhair tree), and Taxales (including yews). Apart from the ginkgo and the larches (conifers), most gymnosperm trees are evergreen. There are also a few l.
Iving trees in the pteridophyte group, known as tree ferns. In the swamp forests of the Carboniferous era, 300 million years ago, there were giant treelike horsetails and club mosses in addition to the tree ferns. The world's oldest trees are found in the Pacific forest of North America, some more than 2,000 years old.

To chase a bear up a tree with dogs and kill it.

Sir Herbert (Draper) Beerbohm 1853-1917 English actor-manager

A data structure containing zero or more nodes that are linked together in a hierarchical fashion. If there are any nodes, one node is the root; each node except the root is the child of one and only one other node; and each node has zero or more nodes as children. See also child (definition 2), graph, leaf, node (definition 3), parent/child (definition 2), root.