Aneurysm

n. abnormal expansion of blood vessel containing clotted blood (Medical)

For the Nirvana song see Aneurysm (song). An aneurysm (or aneurism) is a localized, blood-filled dilation (bulge) of a blood vessel caused by disease or weakening of the vessel wall. Aneurysms most commonly occur in arteries at the base of the brain (the circle of Willis) and in the aorta (the main artery coming out of the heart), a so-called aortic aneurysm. The bulge in a blood vessel can burst and lead to death at any time. The larger an aneurysm becomes, the more likely it is to burst. Aneurysms can usually be treated.
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Aneurysm /an·eu·rysm/ a sac formed by localized dilatation of the wall of an artery, a vein, or the heart. [more]Aneurysm - Community and Resources

Noun
1. a cardiovascular disease characterized by a sac-like widening of an artery resulting from weakening of the artery wall
(synonym) aneurism
(hypernym) cardiovascular disease
(hyponym) aortic aneurysm

A widening or dilatation of blood vessel.

aneurysm or aneurism

noun
swelling caused by the weakening of a wall of a blood vessel
congenital aneurysm = weakening of the arteries at the base of the brain, occurring in a baby from birth
COMMENT: aneurysm usually occurs in the wall of the aorta, ('aortic aneurysm') and is often due to atherosclerosis, and sometimes to syphilis