Hi Kiara.

The Oxford English Dictionary online says that the prefix is from Latin (undecim = eleven). I presume you already know that the suffix is from Greek (gonia = angle).

So, like many words in the English language, it is a hybrid from two sources.

The other name for an undecagon is hendecagon, which is just based on Greek. Some purists believe this is a "better" name because it is more consistent with the other polygon names, but as Juliet said in Romeo and Juliet, "That which we call a rose by any other name would smell as sweet..." I wonder what word Shakespeare would use for an 11-sided figure.

Stephen La Rocque.>

Kiara,

Some of us who are not purists call it an 11-gon.

Penny