Polygons are classified according to the number of sides they have. A polygon with *n* sides is called an *n*-gon. The following lists some of the names of polygons, depending on the number of sides. It is also possible to substitute *“n*-gon,” when the name is not known (for example 14-gon or 20-gon).

**Sides** |
**Polygon Name** |

3 |
trigon or triangle |

4 |
quadrilateral or tetragon |

5 |
pentagon |

6 |
hexagon |

7 |
heptagon |

8 |
octagon |

9 |
nonagon or enneagon |

10 |
decagon |

11 |
hendecagon or undecagon (even less frequently as unidecagon) |

12 |
dodecagon |

13 |
tridecagon or triskaidecagon |

14 |
tetradecagon or tetrakaidecagon |

15 |
pentadecagon or pentakaidecagon |

16 |
hexadecagon or hexakaidecagon |

17 |
heptadecagon or heptakaidecagon |

18 |
octadecagon or octakaidecagon |

19 |
enneadecagon or enneakaidecagon |

20 |
icosagon |

30 |
triacontagon |

40 |
tetracontagon |

50 |
pentacontagon |

60 |
hexacontagon |

70 |
heptacontagon |

80 |
octacontagon |

90 |
enneacontagon |

100 |
hectogon or hecatontagon |

1,000 |
chiliagon |

10,000 |
myriagon |

Some texts list a two-sided polygon as a “digon,” but this is only meant for theoretical mathematics. If you feel like making up your own name, try constructing some sided polygons. For example, a 46-sided polygon could be called a tetracontakai-hexagon, or a combination of “tetracon-tagon” + “kai” (often used in combining names) + “hexagon.” To shorten such long names, mathematicians often use “n-gon” to simplify matters; thus, 46 would be 46-gon a much easier name to remember and even say.

The parts of a polygon.