A polygon is a plane figure that has "at least three straight sides and angles," according to Oxford Dictionaries. However, polygons can have more than three sides; most have five or more.
The word polygon comes from the Greek roots "poly," meaning many and "gon," meaning angle. When naming polygons, the appropriate Greek number replaces the root for the poly. For example, the word pentagon, which describes a five-sided polygon, comes the Greek word for five, "penta." Some other polygons are the heptagon, the tridecagon, the heptacontagon and the hexahectaheptacontakaidigon. These shapes have seven, 13, 70 and 672 sides, respectively. For polygons with more than 10 sides, many mathematicians use the more manageable "n-gon" form; for example, they call the hexahectaheptacontakaidigon a "672-gon."