Lozenge

$\begin{figure}\begin{center}\BoxedEPSF{Lozenge.epsf scaled 800}\end{center}\end{figure}$

An equilateral Parallelogram whose Acute Angles are 45°. Sometimes, the restriction to 45° is dropped, and it is required only that two opposite angles are acute and the other two obtuse. The term Rhombus is commonly used for an arbitrary equilateral parallelogram.

See also Parallelogram, Quadrilateral, Rhombus