Arteriosclerotic aneurysm: A localized widening (aneurysm) of a vessel that occurs because the vessel wall is weakened by arteriosclerosis. An aneurysm is a localized widening (dilatation) of an artery, vein, or the heart. At the area of an aneurysm, there is typically a bulge and the wall is weakened and may rupture.

The word "aneurysm" comes from the Greek "aneurysma" meaning "a widening." Also called an atherosclerotic aneurysm.