/ Dictionary / Index P propylene group: Meaning and Definition of Find definitions for: pro'pylene group" Pronunciation: [key] — Chem. Chem. the bivalent group −CH(CH)CH−, derived from propylene or propane. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. propylene glycol propyl group Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language