# digon

## English

### Etymology

PIE word
*dwóh₁
PIE word
*ǵónu

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

### Pronunciation

• (Received Pronunciation) IPA(key): /ˈdaɪɡən/, /ˈdaɪˌɡɒn/
•  Audio (Southern England) (file)
• (General American) IPA(key): /ˈdaɪɡən/, /ˈdaɪˌɡɑn/
• Hyphenation: di‧gon

### Noun

digon (plural digons)

1. (geometry) A polygon having two edges and two vertices.
Synonyms: biangle, bigon, (less common) diangle
• 2013, Brent Davis; Moshe Renert, chapter 6, in The Math Teachers Know: Profound Understanding of Emergent Mathematics, New York, N.Y.; Abingdon, Oxfordshire: Routledge, →ISBN, page 102:
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. (graph theory)
1. A pair of parallel undirected edges in a multigraph.
2. A pair of antiparallel edges in a directed graph.

## Esperanto

### Noun

digon

1. accusative singular of digo

## French

### Noun

digon m (plural digons)

1. digon

## Welsh

### Etymology

Deverbal from digoni (to be able, to suffice), from a Proto-Celtic *dīkān-: *dī- (from, of) + possibly the root *kān- (sound) that also appears in gwogawn (glory), gogoniant (splendour).[1]

### Noun

digon m (uncountable)

1. enough, plenty, a sufficient amount

#### Derived terms

digon

1. enough, sufficient

### Mutation

Welsh mutation
radical soft nasal aspirate
digon ddigon nigon unchanged
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.

### References

1. ^ R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present), “digon”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies