vein
1. any of the tubular vessels that convey oxygen-depleted blood to the heart
2. any of the hollow branching tubes that form the supporting framework of an insect's wing
3. any of the vascular strands of a leaf
4. a clearly defined mass of ore, mineral, etc., filling a fault or fracture, often with a tabular or sheetlike shape
5. a natural underground watercourse
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
vein
[vān] (anatomy)
A relatively thin-walled blood vessel that carries blood from capillaries to the heart in vertebrates.
(botany)
One of the vascular bundles in a leaf.
(geology)
A mineral deposit in tabular or shell-like form filling a fracture in a host rock.
(invertebrate zoology)
One of the thick, stiff ribs providing support for the wing of an insect.
A venous sinus in invertebrates.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
Vein
a mineral body filling a fissure in rock. Simple veins are single mineralized fissures; complex veins are clusters of interwoven fissures or of zones of fracturing or schist formation. According to their morphological details veins are called lenticular, chambered, saddle-reef, ladder, or feather. Veins that cut across the layers of enclosing rock are called intersecting veins; those that lie in conformity with the stratification and dip of the enclosing rock are called stratified. The length of veins of mineral products varies from 1 m or less to 200 km—for example, the veins of gold ore in California. In terms of dip some veins taper off close to the earth’s surface, and others, for example, the vein of the Kolar deposit in India, are worked at a depth of more than 3 km. A vein has a geological and a working thickness, the minimum thickness for exploiting the vein deposit. Depending on the value of the constituent minerals, the working thickness of a vein may vary from several centimeters to dozens of meters.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.