/ Dictionary / Index D defibrillator: Meaning and Definition of Find definitions for: de•fi•bril•la•tor Pronunciation: (dē-fī'bru-lā"tur, -fib'ru-), [key] — n. Med. an agent or device for arresting fibrillation of the atrial or ventricular muscles of the heart. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: defibrillator (Thesaurus) defibrillate defibrinate Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language