Is a Polygon 8 sided

A polygon can have 8 sides but does not have to.

The Word "Polygon" is made up of two Words: "poly-" and "-gon" which have Greek roots which mean "many" and "angle" respectively; literally a "polygon" is a "many angled shape".

A polygon is any shape that has 3 or more sides.

An 8 sided polygon is called an octagon (literally "eight angles").