nonagonal

Having nine sides and nine angles.

Adjective

  1. Having nine sides and nine angles.

Origin

Etymology tree English nonagon Proto-Indo-European *h₂el-der.? Proto-Italic *-ālis Latin -ālisbor. Old French -albor. ▲ Latin -ālis Old French -elbor. ▲ Latin -ālisbor. Middle English -al English -al English nonagonal From nonagon + -al.