/ Dictionary / Index N nonagon: Meaning and Definition of Find definitions for: non•a•gon Pronunciation: (non'u-gon"), [key] — n. a polygon having nine angles and nine sides. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: nonagon (Thesaurus) nonaggression nonagricultural Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language