Enneagon

En'ne·a·gon noun [ Greek 'enne`a nine + gwni`a corner, angle: confer ennéagone .] (Geom.) A polygon or plane figure with nine sides and nine angles; a nonagon.
Found on http://www.encyclo.co.uk/webster/E/44

Enneagon

• (n.) A polygon or plane figure with nine sides and nine angles; a nonagon.
Found on http://thinkexist.com/dictionary/meaning/enneagon/

enneagon

nonagon, nonagonal; enneagon A polygon having nine angles and nine sides.
Found on http://www.wordinfo.info/words/index/info/view_unit/1409/

enneagon

polygon with nine sides
Found on http://phrontistery.info/e.html
No exact match found