/ Dictionary / Index F fibrillate: Meaning and Definition of Find definitions for: fi•bril•late Pronunciation: (fī'bru-lāt", fib'ru-), [key] — v., -lat•ed, -lat•ing. —v.t. to cause to undergo fibrillation. —v.i. to undergo fibrillation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fibrillate (Thesaurus) fibrilla fibrillation Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language