/ Dictionary / Index O octagon: Meaning and Definition of Find definitions for: oc•ta•gon Pronunciation: (ok'tu-gon", -gun), [key] — n. a polygon having eight angles and eight sides. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: octagon (Thesaurus) octadecanoic acid octagonal Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language