Wiktionary
arteriovenous fistula
n. an abnormal connection between an artery and a vein
Wikipedia
Arteriovenous fistula
An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein. It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial aneurysm.