The term 'half-rectangle shape' can be abbreviated as ELL, which is a three letter acronym. An ELL is a two-dimensional geometric shape that is half of a rectangle. It is a closed figure with two straight sides and two curved sides. The curved sides are usually semicircles, but they can also be arcs of other shapes. Ells are used in many areas of mathematics, engineering, and architecture. They are also used to create logos and other graphic designs.