A 3D display is the display device capable of conveying a stereoscopic perception of 3-D depth to the viewer. The basic technique is to present offset images that are displayed separately to the left and right eye. Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth. Although the term "3D" is ubiquitously used, it is important to note that the presentation of dual 2-D images is distinctly different from displaying an image in three full dimensions. The most notable difference is that, in the case of 3D displays, the observer's head movement will not increase information about the 3-dimensional objects being displayed. Holographic displays do not have this limitation.

Similar to how in sound reproduction it is not possible to recreate a full 3-dimensional sound field merely with two stereophonic speakers, it is likewise an overstatement of capability to refer to dual 2-D images as being "3D". The accurate term "stereoscopic" is more cumbersome than the common misnomer "3D", which has been entrenched after many decades of unquestioned misuse.