/ Dictionary / Index C crustal: Meaning and Definition of Find definitions for: crus•tal Pronunciation: (krus'tl), [key] — adj. of or pertaining to a crust, as of the earth. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: crustal (Thesaurus) crustaceous crustal plate Related Content Daily Word Quiz: boorish Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language