/ Dictionary / Index C clastic: Meaning and Definition of Find definitions for: clas•tic Pronunciation: (klas'tik), [key] — adj. breaking up into fragments or separate portions; dividing into parts. pertaining to an anatomical model made up of detachable pieces. noting or pertaining to rock or rocks composed of fragments or particles of older rocks or previously existing solid matter; fragmental. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: clastic (Thesaurus) clast clathrate Related Content Daily Word Quiz: ontiguous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language