Spherical lune
Area on a sphere bounded by two semicircles joined at antipodal points / From Wikipedia, the free encyclopedia
For the plane geometry region, see Lune (geometry).
This article is about the surface. For the volume, see Spherical wedge.
In spherical geometry, a spherical lune (or biangle) is an area on a sphere bounded by two half great circles which meet at antipodal points.[1] It is an example of a digon, {2}θ, with dihedral angle θ.[2] The word "lune" derives from luna, the Latin word for Moon.