/ Dictionary / Index P phosphorus trichloride: Meaning and Definition of Find definitions for: phos'phorus trichlo'ride Pronunciation: [key] — Chem. Chem. a clear, colorless, fuming liquid, PCl, used chiefly in organic synthesis as a chlorinating agent. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. phosphorus sesquisulfide phosphorylase Related Content Daily Word Quiz: lunar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language