A hendecagon is an 11-sided polygon, also variously known as an undecagon or unidecagon. The term "hendecagon" is preferable to the other two since it uses the Greek prefix and suffix instead of mixing a Roman prefix and Greek suffix.

What is the meaning of a hendecagon?

hendecagon. / (hɛnˈdɛkəɡən) / noun. a polygon having 11 sides.

How many sides does hendecagon?

In geometry, a hendecagon (also undecagon or endecagon) or 11-gon is an eleven-sided polygon.