| any of the vessels, as arteries, veins, or capillaries, through which the blood circulates. |

The flexible tubular canals through which blood circulates in the body. Arteries, veins, and capillaries are all kinds of blood vessels. (See circulatory system.)
blood vessel n.
An elastic tubular channel, such as an artery, a vein, a sinus, or a capillary, through which the blood circulates.