noun Pathology.
- a permanent cardiac or arterial dilatation usually caused by weakening of the vessel wall.
noun
- a sac formed by abnormal dilation of the weakened wall of a blood vessel
early 15c., from Medieval Latin aneurisma, from Greek aneurysmos “dilation,” from aneurynein “to dilate,” from ana- “up” (see ana-) + eurynein “widen,” from eurys “broad, wide,” from PIE root *were- “wide, broad” (cf. Sanskrit uruh “broad, wide”).
n.
- A localized, blood-filled dilation of a blood vessel caused by disease or weakening of the vessel wall.
- A localized, blood-filled dilation of a blood vessel or cardiac chamber caused by disease, such as arteriosclerosis, or weakening of the vessel or chamber wall. A ruptured aneurysm results in hemorrhage and is often fatal.