also: にかっけい
digon
A polygon with two sides and two vertices; in Euclidean geometry this is degenerate, but it exists in spherical geometry.
On a spherical surface, a digon can be defined.
A digon is considered a degenerate polygon in Euclidean geometry.
Triangle, the simplest non-degenerate polygon in Euclidean geometry.
dodecagon
Standard kanji spelling for this geometric term.
Alternate reading with gemination; less common but recognized.
Compound of 二 (two) + 角 (angle) + 形 (shape). A straightforward Sino-Japanese coinage for the geometric concept of a digon.