Digon

//ˈdaɪɡən// noun

noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    A polygon having two edges and two vertices.

    "They [the students] also came upon new and unusual mathematical figures: the digon, a two-sided polygon on a spherical space, and the apeirogon, an open polygon with infinitely many sides […]. All these discoveries brought up even more questions. Is a circle a polygon? What makes an octagon an octagon – its eight vertices, its eight sides, or both? Can a polygon cross itself? Does a polygon need to be closed?"

  2. 2
    A pair of parallel undirected edges in a multigraph.
  3. 3
    A pair of antiparallel edges in a directed graph.

Example

More examples

"They [the students] also came upon new and unusual mathematical figures: the digon, a two-sided polygon on a spherical space, and the apeirogon, an open polygon with infinitely many sides […]. All these discoveries brought up even more questions. Is a circle a polygon? What makes an octagon an octagon – its eight vertices, its eight sides, or both? Can a polygon cross itself? Does a polygon need to be closed?"

Etymology

From di- (prefix meaning ‘two’) + -gon (suffix forming the names of plane figures containing a given number of angles).

Related phrases

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.