WordNet (r) 3.0 (2006):

coronary artery bypass graft
    n 1: open-heart surgery in which the rib cage is opened and a
         section of a blood vessel is grafted from the aorta to the
         coronary artery to bypass the blocked section of the
         coronary artery and improve the blood supply to the heart
         [syn: coronary bypass, coronary bypass surgery,
         coronary artery bypass graft, CABG]