nonagon

American  

[non-uh-gon, -guhn] / ˈnɒn əˌgɒn, -gən /

noun

1. a polygon having nine angles and nine sides.

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nonagon British  

/ nɒnˈæɡənəl, ˈnɒnəˌɡɒn /

noun

1. Also called: enneagon.  a polygon having nine sides

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Other Word Forms

• nonagonal adjective

Etymology

Origin of nonagon

1680–90; < Latin nōn ( us ) ninth + -a- (extracted from pentagon, hexagon, etc.) + -gon

Example Sentences

And while the book is educational, technically, introducing kids to shapes from a simple square to a nonagon, the lesson is beside the point.

From New York Times

And in geometry, an enneagon or nonagon is a nine-sided shape.

From BBC

Illustrations of the former are the bonds between cube root, hectare, brokerage, commission, indorsement, vertex, adjacent, nonagon, sector, draft, bill of exchange, and their meanings.

From Project Gutenberg