Einstein Cross Definition

noun

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

Wiktionary

Origin of Einstein Cross

Einstein (“Albert Einstein ") +‎ cross EINSTEIN CROSS . 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 .)

From Wiktionary