Enneagram (geometry)

Enneagram
Enneagram
	Enneagrams shown as sequential stellations
Edges and vertices	9
Symmetry group	Dihedral (D9)
Internal angle (degrees)	100° {9/2}; 20° {9/4}

In geometry, an enneagram (🟙 U+1F7D9) is a nine-pointed plane figure. It is sometimes called a nonagram, nonangle, or enneagon.^[1]

The word 'enneagram' combines the numeral prefix ennea- with the Greek suffix -gram. The gram suffix derives from γραμμῆ (grammē) meaning a line.^[2]

^ "Between a square rock and a hard pentagon: Fractional polygons". 28 September 2017.
^ γραμμή, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus.

[1] "Between a square rock and a hard pentagon: Fractional polygons". 28 September 2017.

[2] γραμμή, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus.

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