/ Dictionary / Index F fortissimo: Meaning and Definition of Find definitions for: for•tis•si•mo Pronunciation: (fôr-tis'u-mō"It.fôr-tēs'sē-mô"), [key] — Music. Music. —adj. (a direction) very loud. —adv. (a direction) very loudly. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fortissimo (Thesaurus) fortis fortition Related Content Daily Word Quiz: dormant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language