A monogon is a two-dimensional polygon with a single edge. In Euclidean space, it is degenerate, with the edge being of zero length and the shape having no area, but it can exist as a tiling of the circle with the edge taking up the whole circle. Another name for it is henagon.
All monogons are regular, because they only have one vertex and one edge.
Structure and Sections
|Regular ||Rectified ||Truncated ||Monogon||Monogon||Digon|