1) Welsh boy name 
In geometry, a digon or 2-gon is a polygon with two sides (edges) and two vertices. It is degenerate in a Euclidean space, but may be non-degenerate in a spherical space as a pair of 180 degree arcs connecting antipodal points. In Euclidean space a digon is regular, because its two edges are the same length and its two angles are equal (both being...