/ Dictionary / Index P pentadecagon: Meaning and Definition of Find definitions for: pen•ta•dec•a•gon Pronunciation: (pen"tu-dek'u-gon"), [key] — n. Geom. a polygon having 15 angles and 15 sides. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pentadactyl pentaerythritol Related Content Daily Word Quiz: serendipity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language