/ Dictionary / Index S syn-: Meaning and Definition of Find definitions for: syn- Pronunciation: [key] a prefix occurring in loanwords from Greek, having the same function as(synthesis; synoptic); used, with the meaning “with,” “together,” in the formation of compound words (synsepalous) or “synthetic” in such compounds (syngas). syn. Pronunciation: [key] synonym. synonymous. synonymy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. symptosis synaeresis Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language