/ Dictionary / Index P propylene: Meaning and Definition of Find definitions for: pro•pyl•ene Pronunciation: (prō'pu-lēn"), [key] — Chem. Chem. —adj. containing the propylene group. —n. a colorless, flammable gas, CH, of the olefin series: used chiefly in organic synthesis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: propylene (Thesaurus) propyl aldehyde propylene glycol Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language