/ Dictionary / Index X xystum: Meaning and Definition of Find definitions for: xys•tum Pronunciation: (zis'tum), [key] — pl. -ta xyst. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. xyster xystus Related Content Daily Word Quiz: philanthropy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language