Dictionary.com
Thesaurus.com

fibrillation

American  
[fib-ruh-ley-shuhn, fahy-bruh-] / ˌfɪb rəˈleɪ ʃən, ˌfaɪ brə- /

noun

  1. the formation of fibrils, or fine fibers or filaments.

  2. Pathology. uncontrolled twitching or quivering of muscle fibers, such as those of the heart.


fibrillation British  
/ ˌfaɪbrɪˈleɪʃən, ˌfɪb- /

noun

  1. a local and uncontrollable twitching of muscle fibres, esp of the heart, not affecting the entire muscle. Atrial fibrillation results in rapid and irregular heart and pulse rate. In ventricular fibrillation , the heart stops beating

  2. irregular twitchings of the muscular wall of the heart, often interfering with the normal rhythmic contractions

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

fibrillation Scientific  
/ fĭb′rə-lā′shən /
  1. A rapid twitching of muscle fibers, as of the heart, that is caused by the abnormal discharge of electrical nerve impulses. Ventricular fibrillation is life-threatening.


Etymology

Origin of fibrillation

First recorded in 1830–40; fibrillate + -ion

Compare meaning

How does fibrillation compare to similar and commonly confused words? Explore the most common comparisons:

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Doctors are changing their referral practices for the Watchman device because there has been a lot of evidence published in recent months about the risk of stroke for people with atrial fibrillation, Mahoney said.

From The Wall Street Journal ● Jul. 29, 2026

Randomized trials, which are considered the most rigorous and reliable study design, have linked caffeine from coffee to a lower risk of atrial fibrillation.

From Science Daily ● Jul. 22, 2026

Several can detect car crashes or spikes in heart rate as a result of tachycardia, along with such conditions as atrial fibrillation and sleep apnea.

From MarketWatch ● May 28, 2026

It’s a common alternative for patients with atrial fibrillation who can’t take long-term blood thinners.

From Barron's ● May 27, 2026

Then he handed the glass to Camilla and, left hand free, reached down and turned the fibrillation into the opening notes of a Scott Joplin rag.

From "The Secret History" by Donna Tartt

Vocabulary.com logo
by dictionary.com

Just like flashcards, but way more fun

Don't take our word for it. Leave the boring studying behind and join VocabTrainer today. You'll learn even faster and never look back.

Take me to Vocabulary.com