/ Dictionary / Index S synosteosis: Meaning and Definition of Find definitions for: syn•os•te•o•sis Pronunciation: (si-nos"tē-ō'sis), [key] — pl. -ses synostosis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. synoptist synostosis Related Content Daily Word Quiz: fidelity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language