/ Dictionary / Index D diastem: Meaning and Definition of Find definitions for: di•a•stem Pronunciation: (dī'u-stem"), [key] — n. Geol. a minor hiatus in an orderly succession of sedimentary rocks. Cf. unconformity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. diastatic diastema Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language