Einstein cross

Etymology
. From the shape of a cross, of four points at roughly square angles around a central object, caused by distortions in the path of light's travel due to Einsteinian relativity (Albert Einstein's general relativity) creating four points out of a single light source behind the off-center central object. An on-center central object results in an Einstein ring.

Noun

 * 1)  A gravitational lens configuration resulting in four duplicated images of the back ground image around the central gravitationally lensing object, in a cross configuration.

Derived terms

 * the first discovered gravitationally-lensed quasar in this configuration