aneurysm

American  

[an-yuh-riz-uhm] / ˈæn yəˌrɪz əm /

Or aneurism

noun

Pathology.

1. a permanent cardiac or arterial dilatation usually caused by weakening of the vessel wall.

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aneurysm British  

/ ˈænjəˌrɪzəm /

noun

1. a sac formed by abnormal dilation of the weakened wall of a blood vessel

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aneurysm Scientific  

/ ăn′yə-rĭz′əm /

1. 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.

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Other Word Forms

• aneurismal adjective
• aneurismally adverb
• aneurysmal adjective
• aneurysmally adverb

Etymology

Origin of aneurysm

First recorded in 1650–60; from Greek aneúrysma “dilation,” equivalent to aneurys- (variant stem of aneurýnein “to dilate,” from an- an- ³ + eurýnein “to widen, broaden”; eury- ) + -ma, noun suffix

Explanation

Sometimes an artery wall weakens in a spot, causing a pouch-like bulge of pooled blood called an aneurysm. If it bursts, it can be life-threatening. While aneurysms can form anywhere, they are most common in the brain and cardiac areas. This is a very serious medical event that can cause injury and even death. Even though aneurysms are potentially deadly, people use the word sometimes in exaggerations. For example, if you see that someone is getting mad, you might say, "Don't have an aneurysm about it!" That just means something like "Take it easy! Don't get so excited."

Example Sentences

He said he was on the sofa watching rugby and saw the players "falling off the screen", so headed to the hospital where doctors told him he had a brain aneurysm "that started to leak".

From BBC • Mar. 29, 2026

After an aneurysm, your former life, free from the threat of death, of brain damage, of another aneurysm, is gone and buried.

From The Wall Street Journal • Mar. 11, 2026

In January 2018, Vinit suffered a severe and abrupt brain aneurysm at the age of 45.

From Slate • Dec. 8, 2025

Kardashian reacted with visible shock, saying the results “explain a lot” about her stress levels as she juggles a sprawling business empire, law studies, an aneurysm recovery, and a highly public personal life.

From Salon • Nov. 29, 2025

I said that it was probably an aneurysm.

From "The Curious Incident of the Dog in the Night-Time" by Mark Haddon