Easton's Bible Dictionary
Tree of life
Stood also in the midst of the garden of Eden (Genesis 2:9; 3:22). Some writers have advanced the opinion that this tree had some secret virtue, which was fitted to preserve life. Probably the lesson conveyed was that life was to be sought by man, not in himself or in his own power, but from without, from Him who is emphatically the Life (John 1:4; 14:6). Wisdom is compared to the tree of life (Proverbs 3:18). The "tree of life" spoken of in the Book of Revelation (Revelation 2:7; 22:2, 14) is an emblem of the joys of the celestial paradise.
Tree of the knowledge of good and evil
Stood in the midst of the garden of Eden, beside the tree of life (Genesis 2, 3). Adam and Eve were forbidden to take of the fruit which grew upon it. But they disobeyed the divine injunction, and so sin and death by sin entered our world and became the heritage of Adam's posterity. (see ADAM.)
Noah Webster's New International Dictionary of the English Language
1. (n.) Any perennial woody plant of considerable size (usually over twenty feet high) and growing with a single trunk.
2. (n.) Something constructed in the form of, or considered as resembling, a tree, consisting of a stem, or stock, and branches; as, a genealogical tree.
3. (n.) A piece of timber, or something commonly made of timber; -- used in composition, as in axletree, boottree, chesstree, crosstree, whiffletree, and the like.
4. (n.) A cross or gallows; as Tyburn tree.
5. (n.) Wood; timber.
6. (n.) A mass of crystals, aggregated in arborescent forms, obtained by precipitation of a metal from solution. See Lead tree, under Lead.
7. (v. t.) To drive to a tree; to cause to ascend a tree; as, a dog trees a squirrel.
8. (v. t.) To place upon a tree; to fit with a tree; to stretch upon a tree; as, to tree a boot. See Tree, n., 3.