/ Dictionary / Index P polygonaceous: Meaning and Definition of Find definitions for: pol•y•go•na•ceous Pronunciation: (pol"ē-gu-nā'shus, pu-lig"u-nā'-), [key] — adj. belonging to the Polygonaceae, the buckwheat family of plants. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. polygon polygraph Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language