what is the term for the definition of vein?
1. vein-a blood vessel that carries blood from the capillaries toward the heart; all veins except the pulmonary vein carry unaerated blood. vena, venous blood vessel. accessory cephalic vein, vena cephalica accessoria-a vein that passes along the radial edge of the forearm and joins the cephalic vein near the elbow.