/ Dictionary / Index H hydroxyl group: Meaning and Definition of Find definitions for: hydrox'yl group" Pronunciation: [key] the univalent group –OH, as in inorganic compounds, such as sodium hydroxide, NaOH, or as in organic compounds, such as ethyl alcohol, CHO. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hydroxylase hydroxyl ion Related Content Daily Word Quiz: wary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language