Stereopticons are devices that use mirrors and lenses to project two images simultaneously, giving the illusion of depth. While stereopticon is the most commonly used term for this type of device, there are other synonyms that can be used. One such synonym is a magic lantern. This term is often used to describe an early form of the stereopticon, which used hand-painted glass slides instead of photographs. Another synonym is a stereo viewer, which is an updated version of the stereopticon that uses digital images and is often found in virtual reality settings. Other less commonly used synonyms include twin-lens viewer, binopter, and diaphanorama.