/ Dictionary / Index P pyrolysis: Meaning and Definition of Find definitions for: py•rol•y•sis Pronunciation: (pī-rol'u-sis), [key] — n. Chem. the subjection of organic compounds to very high temperatures. the resulting decomposition. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: pyrolysis (Thesaurus) pyrolusite pyromagnetic Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language