/ Dictionary / Index P piperonyl butoxide: Meaning and Definition of Find definitions for: pi•per'o•nyl butox'ide Pronunciation: (pi-per'u-nl, pī-, pip'ur-u-nil), [key] — Chem. Chem. a light-brown liquid, CHO, used chiefly as a synergist in certain insecticides. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. piperonal pipe snake 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