A distended and weakened area in the wall of the abdominal aorta: Abdominal aortic aneurysm is more common in those who suffer from atherosclerosis or the progressive narrowing and hardening of the arteries over time.

This is known to occur to some degree with aging, but other risk factors that accelerate this process have been identified, including high cholesterol, high blood pressure, smoking, diabetes, and family history for atherosclerotic disease.