What is the name of a 1,000-sided polygon?

The polygon with 1,000 sides, 1,000 vertices and 1,000 angles is called a chiliagon or a 1,000-gon. The term "chiliagon," with a Greek-derived prefix meaning “thousand,” is a proposed name for the 1,000-sided, two-dimensional shape, but it is seldom used.

Polygons with 13 or more sides are usually named using the "-gon" form. Therefore, if a figure has 1,000 sides, it is referred to as a 1,000-gon. The word chiliagon was used by some philosophers, such as René Descartes and Immanuel Kant, to describe issues on the subject of thought.

A 1,000-gon consisting of equal sides and equal angles is referred to as a regular 1,000-gon. Otherwise, it is called an irregular 1,000-gon.