leaf

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

• noun A usually green, flattened, lateral structure attached to a stem and functioning as a principal organ of photosynthesis and transpiration in most plants.
• noun A leaflike organ or structure.
• noun Leaves considered as a group; foliage.
• noun The state or time of having or showing leaves.
• noun The leaves of a plant used or processed for a specific purpose.
• noun Any of the sheets of paper bound in a book, each side of which constitutes a page.
• noun A very thin sheet of material, especially metal.
• noun Such leaves considered as a group.
• noun A hinged or removable section for a table top.
• noun A hinged or otherwise movable section of a folding door, shutter, or gate.
• noun A section of drawbridge that moves upward or to the side.
• noun One of several metal strips forming a leaf spring.
• intransitive verb To produce leaves; put forth foliage.
• intransitive verb To turn pages, as in searching or browsing.
• intransitive verb To turn through the pages of.
• idiom (take a leaf from (someone)) To use (someone) as an example.
• idiom (take a leaf from/out of) To use (someone) as an example.

from The Century Dictionary.

• To shoot out leaves; produce foliage: as, the trees leaf in May. Also leave.
• noun An expanded, usually green, organ of a plant, of transient duration, produced laterally from a stem or branch, and, with others, arranged upon the stem in a definite and symmetrical order.
• noun Anything resembling a leaf, as in being flat and relatively broad, or in being a flexible or movable attachment or addition to something else.
• noun A separately movable division of a folding or sliding door, fire-screen, table, hinge, etc.
• noun A very thin sheet of hammered metal; foil: as, gold- leaf.
• noun A portion of fat lying in a separate fold or layer; especially, the fat about the kidneys of a pig (compare leaf-lard); hence, in local use, the kidney itself.
• noun A tooth of a pinion, especially when the pinion is small.
• noun In architecture, an ornament resembling or representing a leaf of a plant; a foliation.
• noun A flap, as of a hat.
• noun In tapestry-weaving, one half the threads of the warp. As a preliminary to working a tapestry these leaves are separated, one being brought nearer the workman and the other left in the background.
• noun In zoology, a leaf-like part or organ. See noseleaf, and compare leaflet, 4.
• noun A distemper in young lambs caused by feeding on leaves

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

• intransitive verb To shoot out leaves; to produce leaves; to leave.
• noun (Bot.) A colored, usually green, expansion growing from the side of a stem or rootstock, in which the sap for the use of the plant is elaborated under the influence of light; one of the parts of a plant which collectively constitute its foliage.
• noun (Bot.) A special organ of vegetation in the form of a lateral outgrowth from the stem, whether appearing as a part of the foliage, or as a cotyledon, a scale, a bract, a spine, or a tendril.
• noun Something which is like a leaf in being wide and thin and having a flat surface, or in being attached to a larger body by one edge or end
• noun A part of a book or folded sheet containing two pages upon its opposite sides.
• noun A side, division, or part, that slides or is hinged, as of window shutters, folding doors, etc.
• noun The movable side of a table.
• noun A very thin plate.
• noun A portion of fat lying in a separate fold or layer.
• noun One of the teeth of a pinion, especially when small.
• noun (Zoöl.) any beetle which feeds upon leaves; esp., any species of the family Chrysomelidæ, as the potato beetle and helmet beetle.
• noun a draw-bridge having a platform or leaf which swings vertically on hinges.
• noun (Bot.) a bud which develops into leaves or a leafy branch.
• noun (Zoöl.) any butterfly which, in the form and colors of its wings, resembles the leaves of plants upon which it rests; esp., butterflies of the genus Kallima, found in Southern Asia and the East Indies.
• noun (Zoöl.) a small moth (Phycis indigenella), the larva of which feeds upon leaves of the apple tree, and forms its nest by crumpling and fastening leaves together in clusters.
• noun the fat which lies in leaves or layers within the body of an animal.
• noun (Zoöl.) a jumping plant louse of the family Psyllidæ.