[non-uh-gon, -guh n]


a polygon having nine angles and nine sides.

Origin of nonagon

1680–90; < Latin nōn(us) ninth + -a- (extracted from pentagon, hexagon, etc.) + -gon
Also called enneagon.
Related formsnon·ag·o·nal [non-ag-uh-nl] /nɒnˈæg ə nl/, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for nonagon


Examples from the Web for nonagon

Historical Examples of nonagon

  • There is said to be only one triangle, only one nonagon, and only one of diamond shape in all the forty thousand.

    One Irish Summer

    William Eleroy Curtis

British Dictionary definitions for nonagon



a polygon having nine sidesAlso called: enneagon
Derived Formsnonagonal (nɒnˈæɡənəl), adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for nonagon

"plane figure with nine sides," 1680s, a hybrid from Latin nonus "ninth" (see nones) + ending from pentagon, etc.

Online Etymology Dictionary, © 2010 Douglas Harper