A 3D display is a technology that creates the illusion of depth in images, allowing viewers to perceive three-dimensional visuals. This is achieved through various methods, such as stereoscopy, which uses two slightly different images for each eye, or holography, which captures light fields to produce realistic 3D images. These displays are commonly used in virtual reality headsets, 3D movies, and gaming to enhance the viewing experience. They can also be found in specialized applications like medical imaging and scientific visualization, where depth perception is crucial for analysis and interpretation.