Definitions
from Wiktionary, Creative Commons Attribution/ShareAlike License
 n. (rare) A polygon with a thousand vertices and a thousand edges.
from the GNU version of the Collaborative International Dictionary of English
 n. A plane figure of a thousand angles and sides.
from The Century Dictionary and Cyclopedia
 n. A plane figure of a thousand angles and sides.
Etymologies
from Wiktionary, Creative Commons Attribution/ShareAlike License
Examples

Also, there were things such as Descartes 'chiliagon which, while they could be represented physically, could not (as experience shows) be represented accurately by our physical imaging system.

When we think of a perfect triangle, or a chiliagon, or even of some possible animal not actually existent, the object of our thought, the objective concept, is a possible essence.

'Tis impossible for the eye to determine the angles of a chiliagon to be equal to 1996 right angles, or make any conjecture, that approaches this proportion; but when it determines, that right lines cannot concur; that we cannot draw more than one right line between two given points; it's mistakes can never be of any consequence.

a chiliagon to be equal to 1996 right angles, or make any conjecture, that approaches this proportion; but when it determines, that right lines cannot concur; that we cannot draw more than one right line between two given points; it's mistakes can never be of any consequence.

It is impossible for the eye to determine the angles of a chiliagon to be equal to 1996 right angles, or make any conjecture, that approaches this proportion; but when it determines, that right lines cannot concur; that we cannot draw more than one right line between two given points; it’s mistakes can never be of any consequence.
bilby commented on the word chiliagon
A multihabanerosided figure.
November 25, 2009