octagon

is symbolic of spiritual regeneration, because the eight-sided figure is connected with this idea as the intermediary between the square and the circle.

Octagon Embellishments, architectonic structures, and different dispositions based on the octagon (in ground-plan or elevation in the case of a building or structure such as a baptistry, fountain, etc.) symbolize spiritual regeneration, because the eight-sided figure is connected with this idea as the intermediary between the square and the circle. It is not surprising, therefore, that the majority of baptistries have a definite octagonal shape. However, twelve is sometimes used for baptismal fonts (the sum of the facets of the semi-polyhedron), because it symbolizes totality.

octagon, n.Definitions

octagon