TREE (O. Eng. treo, treow, cf. Dan. trae, Swed. trad, tree, Ira, timber; allied forms are found in Russ. drevo, Gr. 6pDs, oak, and dopv, spear, Welsh derw, Irish darog, oak, and Skr. ddru, wood) , the term, applied in a wide sense, to all plants which grow with a permanent single woody stem or trunk of some height, branching out at some distance from the ground. There is a somewhat vague dividing line, in popular nomenclature, between " shrubs " and " trees," the former term being usually applied to plants with several stems, of lower height, and bushy in growth. The various species to which the name " tree " can be given are treated under their individual titles, e.g. oak, ash, elm, etc. ; the articles FIR and PINE treat of two large groups of conifers; general information is provided by the articles PLANTS and GYMNOSPERMS; tree cultivation will be found under FORESTS AND FORESTRY and HORTICULTURE; and the various types of tree whose wood is useful for practical purposes under TIMBER. Apart from this general meaning of the word, the chief transferred use is that for a piece of wood used for various specific purposes, as a framework, bar, etc., such as the tree of a saddle, axle-tree, cross-tree, etc.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)