noun, verb, treed, tree⋅ing.| 1. | a plant having a permanently woody main stem or trunk, ordinarily growing to a considerable height, and usually developing branches at some distance from the ground. |
| 2. | any of various shrubs, bushes, and plants, as the banana, resembling a tree in form and size. |
| 3. | something resembling a tree in shape, as a clothes tree or a crosstree. |
| 4. | Mathematics, Linguistics. tree diagram. |
| 5. | family tree. |
| 6. | a pole, post, beam, bar, handle, or the like, as one forming part of some structure. |
| 7. | a shoetree or boot tree. |
| 8. | a saddletree. |
| 9. | a treelike group of crystals, as one forming in an electrolytic cell. |
| 10. | a gallows or gibbet. |
| 11. | the cross on which Christ was crucified. |
| 12. | Computers. a data structure organized like a tree whose nodes store data elements and whose branches represent pointers to other nodes in the tree. |
| 13. | Christmas tree. |
| 14. | to drive into or up a tree, as a pursued animal or person. |
| 15. | Informal. to put into a difficult position. |
| 16. | to stretch or shape on a tree, as a boot. |
| 17. | to furnish (a structure) with a tree. |
| 18. | up a tree, Informal. in a difficult or embarrassing situation; at a loss; stumped. |

| Mathematics, Linguistics. a diagram in which lines branch out from a central point or stem without forming any closed loops. |
tree
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"Minc'd Pyes do not grow upon every tree,
But search the Ovens for them, and there they be."
["Poor Robin," Almanack, 1669]
tree mathematics, data
A directed acyclic graph; i.e. a graph wherein there is only one route between any pair of nodes, and there is a notion of "toward top of the tree" (i.e. the root node), and its opposite direction, toward the leaves. A tree with n nodes has n-1 edges.
Although maybe not part of the widest definition of a tree, a common constraint is that no node can have more than one parent. Moreover, for some applications, it is necessary to consider a node's daughter nodes to be an ordered list, instead of merely a set.
As a data structure in computer programs, trees are used in everything from B-trees in databases and file systems, to game trees in game theory, to syntax trees in a human or computer languages.
(1998-11-12)
tree
see bark up the wrong tree; can't see the forest for the trees; talk someone's arm off (the bark off a tree); up a tree.