ETYM Old Eng. veine, French veine, Latin vena.
In animals with a circulatory system, any vessel that carries blood from the body to the heart. Veins contain valves that prevent the blood from running back when moving against gravity. They always carry deoxygenated blood, with the exception of the veins leading from the lungs to the heart in birds and mammals, which carry newly oxygenated blood.
The term is also used more loosely for any system of channels that strengthens living tissues and supplies them with nutrients —for example, leaf veins (see vascular bundle), and the veins in insects' wings.
(Homonym: vain, vein).
1. A blood vessel that carries blood from the capillaries toward the heart; all veins except the pulmonary carry unaerated blood; SYN. vena.
2. A distinctive style or manner.
3. One of the horny ribs that stiffen and support the wing of an insect; SYN. nervure.
4. One of the vascular bundles or ribs that form the branching framework of conducting and supporting tissues in a leaf or other plant organ; SYN. nervure.