Polygon Names

Polygon names | Name | Edges | Remarks | henagon (or monogon) | 1 | In the Euclidean plane, degenerates to a closed curve with a single vertex point on it. | digon | 2 | In the Euclidean plane, degenerates to a closed curve with two vertex points on it. | triangle (or trigon) | 3 | The simplest polygon which can exist in the Euclidean plane. | quadrilateral (or quadrangle or tetragon) | 4 | The simplest polygon which can cross itself. | pentagon | 5 | The simplest polygon which can exist as a regular star. A star pentagon is known as a pentagram or pentacle. | hexagon | 6 | Avoid "sexagon" = Latin [sex-] + Greek. | heptagon | 7 | Avoid "septagon" = Latin [sept-] + Greek. The simplest polygon such that the regular form is not constructible with compass and straightedge. However, it can be constructed using a Neusis construction. | octagon | 8 | | enneagon or nonagon | 9 | "Nonagon" is commonly used but mixes Latin [novem = 9] with Greek. Some modern authors prefer "enneagon", which is pure Greek. | decagon | 10 | | hendecagon | 11 | Avoid "undecagon" = Latin [un-] + Greek. The simplest polygon such that the regular form cannot be constructed with compass, straightedge, and angle trisector. | dodecagon | 12 | Avoid "duodecagon" = Latin [duo-] + Greek. | tridecagon (or triskaidecagon) | 13 | | tetradecagon (or tetrakaidecagon) | 14 | | pentadecagon (or quindecagon or pentakaidecagon) | 15 | | hexadecagon (or hexakaidecagon) | 16 | | heptadecagon (or heptakaidecagon) | 17 | | octadecagon (or octakaidecagon) | 18 | | enneadecagon (or enneakaidecagon or nonadecagon) | 19 | | icosagon | 20 | | triacontagon | 30 | | hectogon | 100 | "hectogon" is the Greek name (see hectometer), "centagon" is a Latin-Greek hybrid; neither is widely attested. | chiliagon | 1000 | René Descartes, Immanuel Kant, David Hume, and others have used the chiliagon as an example in philosophical discussion. | myriagon | 10,000 | |