Spherical lune
![The two great circles are shown as thin black lines, whereas the spherical lune (shown in green) is outlined in thick black lines. This geometry also defines lunes of greater angles: 2π-θ, and 22π-θ.](/Images/godic/202502/12/Regular_digon_in_spherical_geometry-2.svg3903.png")
![A full circle lune, 22π](/Images/godic/202502/12/Spherical_lune_3603903.png")
![The phases of the moon make spherical lunes perceived as the intersection of a semicircle and semi-ellipse.](/Images/godic/202502/12/The_Moon_Luc_Viatour3903.jpg")
![Stereographic projection of the 3-sphere's parallels (red), meridians (blue) and hypermeridians (green). Lunes exist between pairs of blue meridian arcs.](/Images/godic/202502/12/Hypersphere_coord3903.PNG")
In spherical geometry, a spherical lune is an area on a sphere bounded by two half great circles which meet at antipodal points, and is an example of a digon, {2}θ, with dihedral angle θ. The word "lune" derives from luna, the Latin word for Moon.
A spherical wedge is the volume of space bounded by two planes passing through a sphere center and the surface of the sphere.