/ Dictionary / Index H hydrogen iodide: Meaning and Definition of Find definitions for: hy'drogen i'odide Pronunciation: [key] a colorless gas, HI, having a suffocating odor: the anhydride of hydriodic acid. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hydrogen fluoride hydrogen ion 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