/ Dictionary / Index C chromium dioxide: Meaning and Definition of Find definitions for: chro'mium diox'ide Pronunciation: [key] a strongly magnetic, black, semiconducting substance, CrO, used as the active material in a type of recording tape. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. chromium chloride chromium oxide Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language