/ Dictionary / Index F fissure of Sylvius: Meaning and Definition of Find definitions for: fis'sure of Syl'vi•us Pronunciation: (sil'vē-us). [key] See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. fissure of Rolando fist Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language