/ Dictionary / Index P peroxy group: Meaning and Definition of Find definitions for: perox'y group" Pronunciation: [key] — Chem. Chem. the bivalent group –O–, derived from hydrogen peroxide. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. peroxydisulfuric acid peroxymonosulfuric acid Related Content Daily Word Quiz: penchant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language