1. of, relating to, or having the shape of a nonagon (a polygon with nine sides and nine angles)
Usage: geometry; technical

Examples

• The architect designed a nonagonal tower with nine equal sides.
• A nonagonal shape has nine interior angles that sum to 1,260 degrees.
• The garden was laid out in a nonagonal pattern.
• Students learned to calculate the area of a nonagonal figure in geometry class.
• The nonagonal base of the monument made it structurally unique.