vein

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Anatomy Any of the membranous tubes that form a branching system and carry blood to the heart.
2. n. A blood vessel.
3. n. Botany One of the vascular bundles or ribs that form the branching framework of conducting and supporting tissues in a leaf or other expanded plant organ. Also called nervure.
4. n. Zoology One of the horny ribs that stiffen and support the wing of an insect. Also called nervure.
5. n. Geology A regularly shaped and lengthy occurrence of an ore; a lode.
6. n. A long wavy strip of a different shade or color, as in wood or marble, or as mold in cheese.
7. n. A fissure, crack, or cleft.
8. n. A pervading character or quality; a streak: "All through the interminable narrative there ran a vein of impressive earnestness” ( Mark Twain). See Synonyms at streak.
9. n. A transient attitude or mood.
10. n. A particular turn of mind: spoke later in a more serious vein.
11. v. To supply or fill with veins.
12. v. To mark or decorate with veins.

Century Dictionary and Cyclopedia

1. n. In anatomy, one of a set of blood-vessels conveying blood from the periphery to the physiological center of the circulation; one of a set of membranous canals or tubes distributed in nearly all the tissues and organs of the body, for the purpose of carrying blood from these parts to the heart. The walls of the veins are thinner, as a rule, and more flaccid, than those of the arteries; they are composed of three layers or coats—the outer or fibrous; the middle, made up chiefly of sparse muscular fibers; and the inner or serous. The inner or lining membrane, especially in the veins of the lower extremities, presents numerous crescentic folds, usually in man occurring in pairs, known as the valves of the veins, which serve to prevent a backward flow of the blood. The nutrition of the walls is provided for by the vasa vasorum. The nerves supplying the walls of the veins are few in number. There are two systems of veins—the systemic, or those carrying venous blood from the tissues of the body to the right auricle of the heart: and the pulmonary, or those carrying the oxygenated blood from the lungs to the left auricle of the heart. The portal system is a subdivision of the systemic, in which blood coming from the digestive organs is conducted to the liver by the portal vein, circulates throughout this organ, is again collected in the hepatic veins, and is thence carried to the right auricle of the heart. The veins of the portal system have no valves. The blood in the systemic veins is dark-red in color, and flows in a continuous stream. The umbilical veins of the fetus, like the pulmonary veins, convey oxygenated or arterial blood. As a general rule, the corresponding veins and arteries run side by side, and are called by the same names. In fishes and other low vertebrates which breathe by gills, the veins from these organs correspond in function, but not morphologically, with pulmonary veins. There is a reniportal system of veins in some animals, as Amphibia and reptiles, by which the kidneys receive blood from veins as well as by renal arteries. See phrases below, and vena. See also cuts under circulation, heart, liver, lung, median, and thorax.
2. n. Loosely, any blood-vessel. Many of the veins being superficial or subcutaneous, liable to ordinary observation, and when swollen or congested very conspicuous, the name is popularized, and extended to the arteries, while artery remains chieliy a technical term.
3. n. In entomology, one of the ribs or horny tubes which form the frame work of the wings of an insect, and between which the thin membrane of the wings is spread and supported; a nervure. Veins result from certain thickenings of the upper and under surfaces of the sac which primarily composes the wing, these thickenings being exactly coapted, and often hollowed or channeled for the reception of air-tubes—which enables the wings to subserve to some extent the functions of lungs. The primary veins give out veinlets or nervnles. The venation of the wings differs much in different insects, but is sufficiently constant in each case to afford valuable classificatory characters. See cuts under Chrysopa, Cirrophanus, nervure, and venation.
4. n. In botany, a fibrovascular bundle at or near the surface of a leaf, sepal, petal, etc.: same as nerve, 7. See nervation.
5. n. In mining, an occurrence of ore. usually disseminated through a gangue or veinstone, and having a more or less regular development in length, width, and depth. A fissure-vein, or true vein, is a vein in which the ore and veinstone occupy a preëxisting flssure or crack in the rocks, which has been formed by some deep-seated cause or crust-movement, and may therefore be presumed to extend downward indefinitely, and for the same reason is likely to have considerable development in length. True veins usually have well-defined walls, on which there is more or less flucan or gouge, and which are often striated or polished, giving rise to what miners call slickensides. True veins often have the ore and veinstone arranged in parallel plates or layers, called combs. Experience shows that true veins are more to be depended on for permanence in depth than other more irregular deposits, although the latter are often highly productive for a time. A vein and a lode are, in common usage, essentially the same thing, the former being rather the scientific, the latter the miner's, name for it. The term deposit, when used by itself, means an irregular occurrence of ore, such as a flat-mass, stock, contact deposit, carbona, and the like; but when to deposits the term ore or metalliferous is prefixed (ore-deposits, metalliferous deposits), the designation becomes the most general one possible, including every form of occurrence of the metalliferous ores, and having the same meaning as the French gites métallifères and the German Erzlagerstätten. A bed of rock forming a member of a stratified formation, with which it was synchronously deposited, cannot properly be called a vein or lode, even if it has metalliferous matter generally disseminated through it in quantity sufficient to be worth working, as is the case with the cupriferous slate (Kupferschiefer) of Mansfeld in Prussia, or when it is concentrated in pipes or pipe-like masses, occurring here and there in the stratum, as in the silver-lead mines of Eureka in Nevada. (See ore-deposit.) Further— for forms of ore-deposits which are not true veins, but which are designated by the name vein, see gash-vein, segregated vein (also segregation), pipe-vein; for forms qualified, according to general usage, by the name deposit (which also see), and which are still further removed from the class of true veins than those previously noted, see contact deposit (under contact), blanket-deposit; for other still more irregular forms of ore-deposit, which have special names, and which, while not themselves properly designated as veins, are frequently more or less closely connected with true veins, occurring in close proximity, and forming a kind of appendage, to them, see flat, 10. pipe, 16, carbona, impregnation, 4; and for German mining terms applied to various irregular forms of ore-deposit, not true veins, which terms are often used by scientific writers in English in describing mining regions or in discussing the general mode of occurrence of the metalliferous ores, see stock, 32, stackwork, fahlband. See also lode, 3, leader, 5 ; also rake-vein, a term applied in Derbyshire, England, to true veins to distinguish them from the flats and pipe-veins with which they are closely connected.
6. n. A cavity, fissure, or cleft, as in the earth or other substance.
7. n. A streak, stripe, or marking, of different color or shade, as in natural marble or wood cut so as to show the grain, or glass in which different colors have been melted irregularly. The term is applied either to a long and nearly regular stripe, or to a much broken and contorted one, returning upon itself. Also called veining.
8. n. A streak; a part of anything marked off from the rest by some distinctive character; hence, a distinct property or characteristic considered as running through or being intermingled with others; a continued strain.
9. n. Manner of speech or action; particular style, character, disposition, or cast of mind.
10. n. Particular mood, temper, humor, or disposition for the time being.
11. To fill or furnish with veins; cover with veins; streak or variegate with or as with veins.

Wiktionary

1. n. anatomy A blood vessel that transports blood from the capillaries back to the heart
2. n. The entrails of a shrimp
3. n. botany In leaves, a thickened portion of the leaf containing the vascular bundle
4. n. zoology The nervure of an insect’s wing
5. n. A stripe or streak of a different colour or composition in materials such as wood, cheese, marble or other rocks
6. n. A topic of discussion
7. n. A style, tendency, or quality of something

GNU Webster's 1913

1. n. (Anat.) One of the vessels which carry blood, either venous or arterial, to the heart. See artery, 2.
2. n. (Bot.) One of the similar branches of the framework of a leaf.
3. n. (Zoöl.) One of the ribs or nervures of the wings of insects. See Venation.
4. n. (Geol. or Mining) A narrow mass of rock intersecting other rocks, and filling inclined or vertical fissures not corresponding with the stratification; a lode; a dike; -- often limited, in the language of miners, to a mineral vein or lode, that is, to a vein which contains useful minerals or ores.
5. n. A fissure, cleft, or cavity, as in the earth or other substance.
6. n. A streak or wave of different color, appearing in wood, and in marble and other stones; variegation.
7. n. A train of associations, thoughts, emotions, or the like; a current; a course.
8. n. Peculiar temper or temperament; tendency or turn of mind; a particular disposition or cast of genius; humor; strain; quality; also, manner of speech or action.
9. v. To form or mark with veins; to fill or cover with veins.

WordNet 3.0

1. n. one of the horny ribs that stiffen and support the wing of an insect
2. v. make a veinlike pattern
3. n. a layer of ore between layers of rock
4. n. any of the vascular bundles or ribs that form the branching framework of conducting and supporting tissues in a leaf or other plant organ
5. n. a distinctive style or manner
6. n. a blood vessel that carries blood from the capillaries toward the heart