/ Dictionary / Index P pyrochlore: Meaning and Definition of Find definitions for: py•ro•chlore Pronunciation: (pī'ru-klôr", -klōr"), [key] — n. a mineral, chiefly composed of niobates of the cerium metals, occurring in syenites in the form of brown crystals. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pyrochemical pyroclastic Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language