/ Dictionary / Index P polypropylene: Meaning and Definition of Find definitions for: pol•y•pro•pyl•ene Pronunciation: (pol"ē-prō'pu-lēn"), [key] — n. Chem. a plastic polymer of propylene, (CH), used chiefly for molded parts, electrical insulation, packaging, and fibers for wearing apparel. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: polypropylene (Thesaurus) polypous polyprotic Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language