Coronary artery disease (CAD) refers to the narrowing or blockage of the coronary arteries, which supply blood to the heart muscle. This condition is typically caused by a buildup of plaque, consisting of cholesterol and other substances, on the artery walls. As the arteries become narrower, blood flow to the heart is reduced, leading to symptoms such as chest pain, shortness of breath, and potentially heart attacks. Therefore, the given answer "coronary artery disease" accurately defines CAD.