1. Plural of enneagon; polygons with nine sides and nine angles.
Usage: geometry; also called nonagon

Examples

• The architect designed the building with enneagons as the base shape.
• In geometry class, students learned to calculate the interior angles of enneagons.
• The artist drew several enneagons to practice drawing regular polygons.
• Enneagons have nine equal sides when they are regular.
• The sum of interior angles in all enneagons is 1,260 degrees.