/ Dictionary / Index C conium: Meaning and Definition of Find definitions for: co•ni•um Pronunciation: (kō'nē-um), [key] — n. the poison hemlock, Conium maculatum. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: conium (Thesaurus) conirostral conj. Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language