What is "dihedral group"

n. (context group theory English) a (l/en: group) of (l/en symmetry symmetries) of a (l/en: regular polygon)

In mathematics, a dihedral group is the group of symmetries of a regular polygon, which includes rotations and reflections. Dihedral groups are among the simplest examples of finite groups, and they play an important role in group theory, geometry, and chemistry.

The notation for the dihedral group of order differs in geometry and abstract algebra. In geometry, or refers to the symmetries of the n-gon, a group of order . In abstract algebra, refers to the dihedral group of order . The geometric convention is used in this article.