1) Blood vessel 
Arteriovenous refers to relations between arteries and veins, such as: ...
both arterial and venous; pertaining to or affecting an artery and a vein.
Relating to both arteries and veins.
<anatomy> Both arterial and venous, pertaining to or affecting an artery and a vein. ... (18 Nov 1997) ... 
(ahr-tēr″e-o-ve´nәs) both arterial and venous; pertaining to both artery and vein.
(AV) Type: Term Pronunciation: ar-tēr′ē-ō-vē′nŭs Definitions: 1. Relating to both an artery and a vein or to both arteries and veins in general; both arterial and venous, as an 'AV anastomosis.'
[adj] - connecting an artery to a vein
adjective connecting an artery to a vein; `an arteriovenous fistula`
of or pertaining to an artery and a vein; having characteristics of both arteries and veins.