/ Dictionary / Index P pinnule: Meaning and Definition of Find definitions for: pin•nule Pronunciation: (pin'yl), [key] — n. a part or organ resembling a barb of a feather, a fin, or the like. a finlet. a secondary pinna, one of the pinnately disposed divisions of a bipinnate leaf. a metal plate with a small hole in it, used as a sight in a quadrant. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: pinnule (Thesaurus) pinnulate pin oak Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language