Old English leef, lef, leaf, Anglo Saxon. leáf; akin to Saxon lf, Old Friesian laf, Dutch loof foliage, German laub, Old High German loub leaf, foliage, Icelandic lauf, Swedish löf, Danish löv, Gothic laufs; compare Lithuanian lapas. Compare lodge.
- (Botany) 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.
- Note: Such leaves usually consist of a blade, or lamina , supported upon a leafstalk or petiole, which, continued through the blade as the midrib, gives off woody ribs and veins that support the cellular texture. The petiole has usually some sort of an appendage on each side of its base, which is called the stipule. The green parenchyma of the leaf is covered with a thin epiderm pierced with closable microscopic openings, known as stomata.
- (Botany): 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.
- Note: In this view every part of a plant, except the root and the stem, is either a leaf, or is composed of leaves more or less modified and transformed.
- 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; as :
- (a) A part of a book or folded sheet containing two pages upon its opposite sides.
- (b) A side, division, or part, that slides or is hinged, as of window shutters, folding doors, etc.
- (c) The movable side of a table.
- (d) A very thin plate; as, gold leaf.
- (e) A portion of fat lying in a separate fold or layer.
- (f) One of the teeth of a pinion, especially when small.
- Leaf metal:, metal in thin leaves, as gold, silver, or tin
- Leaf notcher, (Zoölogy):, a pale bluish green beetle (Artipus floridanus), which, in Florida, eats the edges of the leaves of orange trees
- Leaf scar, (Botany): the cicatrix on a stem whence a leaf has fallen
- Leaf sewer, (Zoölogy): a tortricid moth, whose caterpillar makes a nest by rolling up a leaf and fastening the edges together with silk, as if sewn; especially, Phoxopteris nubeculana, which feeds upon the apple tree
- Leaf tier, (Zoölogy): a tortricid moth whose larva makes a nest by fastening the edges of a leaf together with silk; especially, Teras cinderella, found on the apple tree
- Leaf wasp, (Zoölogy): a sawfly