Aortic arch: The second section of the aorta. The aorta first ascends, then bends, and then descends. The bend is the aortic arch. It gives off the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery. The brachiocephalic trunk, the first branch off the aortic arch, splits to form the right subclavian artery and the right common carotid artery which supply blood, respectively, to the right arm and to the right side of the neck and head. The left common carotid artery and left subclavian artery, the second and third branches off the aortic arch, perform parallel functions on the left side.