/ Dictionary / Index P penninite: Meaning and Definition of Find definitions for: pen•ni•nite Pronunciation: (pen'u-nīt"), [key] — n. Mineral. a member of the chlorite group, rhombohedral in habit. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. penning gate pennon Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language