An abdominal aortic aneurysm (AAA) and atherosclerosis are related but not the same condition. AAA is a bulging or ballooning of the abdominal portion of the aorta—the main artery that carries blood from the heart to the rest of the body. The wall of the aorta weakens and stretches, increasing the risk of rupture. Atherosclerosis, on the other hand, is the buildup of fatty plaques (cholesterol, calcium, and other substances) inside the walls of arteries. This process can weaken the arterial wall over time and is one of the most common causes of AAA. In other words, atherosclerosis often contributes to or accelerates the development of an aneurysm, but not all aneurysms are caused by atherosclerosis. Some are due to genetic factors, connective tissue disorders, inflammation, or trauma.

In short:
Atherosclerosis = plaque buildup inside artery walls.
AAA = a weakened and dilated section of the aorta, often resulting from or worsened by atherosclerosis.

Peace.