What is "vasa vasorum"

n. (context anatomy English) The capillary that supply blood to vessels larger than 1 mm. They supply blood to the adventitia and middle tunicae.

n. any small blood vessel ramifying on the outside of a major artery or vein

The vasa vasorum (Latin, "the vessels of the vessels") is a network of small blood vessels that supply the walls of large blood vessels, such as elastic arteries ( aorta) and large veins ( vena cava).