/ Dictionary / Index O ornithischian: Meaning and Definition of Find definitions for: or•nith•is•chi•an Pronunciation: (ôr"nu-this'kē-un), [key] — n. any herbivorous dinosaur of the order Ornithischia, having a pelvis resembling that of a bird. Cf. —adj. belonging or pertaining to the Ornithischia. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ornithischian (Thesaurus) ornithine ornitho- Related Content Daily Word Quiz: impetuous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language