3-D or 3D abbreviates "three dimensional" and is often related to a stereoscopic display that exploits binocular vision.
Three dimensional objects have volume and may be measured and described using three orthogonal directions.
In animation, 3-D sometimes refers to shaded, modeled shapes that have an apearance of depth, as opposed to the "flat" rendering of conventional cell animation. An example of this was seen in a particular episode of the animated video cartoon The Simpsons, where Homer escapes his flatland-like world and enters a universe of higher dimensionality. The figure renderings and visual effects in this episode were accomplished using 3D computer graphics.
See the following articles:
3D is also the stage name of British artist and musician Robert Del Naja.
3D/Biela is Biela's Comet
http://www.3dprint.ch : Printing your 3D models