/ Dictionary / Index H hydrogen cyanide: Meaning and Definition of Find definitions for: hy'drogen cy'anide Pronunciation: [key] a colorless poisonous gas, HCN, having a bitter almondlike odor: in aqueous solution it forms hydrocyanic acid. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hydrogen chloride hydrogen electrode Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language