In geometry, a digon is a polygon with two sides (edges) and two vertices. Its construction is degenerate in a Euclidean plane because either the two sides would coincide or one or both would have to be curved; however, it can be easily visualised in elliptic space.
A regular digon has both angles equal and both sides equal and is represented by Schläfli symbol {2}. It may be constructed on a sphere as a pair of 180 degree arcs connecting antipodal points, when it forms a lune.
The digon is the simplest abstract polytope of rank 2.
A truncated digon, t{2} is a square, {4}. An alternated digon, h{2} is a monogon, {1}.
Special cases, including regular polygons with their own names, in parentheses List of polygons by number of sides | ||
1–10 sides | ||
11–20 sides | ||
21–30 sides | ||
31–50 sides | ||
51–100 sides (selected) | ||
>100 sides | ||
Star polygons (5–12 sides) | ||
Triangles | ||
Quadrilaterals |