/ Dictionary / Index B butterfly effect: Meaning and Definition of Find definitions for: but'terfly effect" Pronunciation: [key] a cumulatively large effect that a very small natural force may produce over a period of time. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. butterfly damper butterflyfish Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language