
In plane geometry, a lune is the concave-convex area bounded by two circular arcs, while a convex-convex area is termed a lens. The word "lune" derives from luna, the Latin word for Moon.
Formally, a lune is the relative complement of one disk in another (where they intersect but neither is a subset of the other). Alternatively, if A and B are disks, then
L
=
A
−
A
∩
B
{\displaystyle L=A-A\cap B}
is a lune.
== Example ==
In the 5th century BC, Hippocrates of Chios showed that certain lunes could be exactly...