/ Dictionary / Index I isacoustic: Meaning and Definition of Find definitions for: is•a•cous•tic Pronunciation: (ī"su-k'stik or, esp. Brit., ī"su-kou'-), [key] — adj. of or pertaining to two sounds of equal intensity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. isabnormal Isadora 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