Breadcrumb Home > Dictionary > Index F Cite fibrillation: Meaning and Definition of Find definitions for: fi•bril•la•tion Pronunciation: (f?"bru-l?'shun, or, esp. for 2, fib"ru-), [key] ? n. the formation of fibrils. uncontrolled twitching or quivering of muscular fibrils. Random House Unabridged Dictionary, Copyright 1997, by Random House, Inc., on Infoplease. See also: fibrillation (Thesaurus) fibrillate fibrilliform TrendingHere are the facts and trivia that people are buzzing about. February 2021 Current Events: US News The Berlin Conference and the Partition of Africa The Implied Powers of Congress Noble Titles and Ranks in a Monarchy Keeping Your Brain Active in a COVID-19 World The Manchu Related Content Daily Word Quiz: nosegay Analogy of the Day: Today?s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language