2D is the abbreviation of two-dimensional. It refers to "flat" images that are drawn, painted, displayed, printed etc. on a two-dimensional surface such as paper, canvas, or a screen. Most visual artwork is two-dimensional.
2D and 3DEdit
2D is contrasted with 3D. The term 3D is sometimes used for real 3D objects (such as in sculpture) and sometimes for 2D projections of 3D objects that either exist in the real world (as in photography and film) or in a computer model (as in 3D computer graphics).
We must distinguish between:
- 2D art that "looks 2D" and
- 2D art that "looks 3D" (which is also often called "3D" despite the fact that it's on a 2D medium).
The term 2D graphics usually refers to graphics that "look 2D" and are not created using 3D models, such as traditional comics or cartoons. Such graphics are often cel-colored. Note that an artist creating 2D graphics may well have a 3D model of the objects, characters and scenes in his mind and will use this 3D imagination to create a good and correct drawing. If an image that "looks 3D" is desired, this is an absolute necessity. For more on this topic, see 3D Figure Drawing.
The techniques used in realistic, 3D-looking art (such as [perspective]]) were first developed in the Renaissance era. Basically all art of the Middle Ages, Antiquity, and earlier - from whichever continent - was true 2D. Since modernity, the principles of 3D-to-2D projection are well-understood and it's a modern artist's free choice to work in 2D or 3D style. After 3D was no longer a challenge, in the late 19th and early 20th century, 2D art grew once again very popular, e.g. in Art Nouveau and later in the various forms of abstract art.
Computer graphics was initially only possible in 2D because 3D graphics requires very fast computers. Since the 1990s, 2D and 3D graphics coexist, and 2D as well as 3D graphics became more and more photorealistic. In the computer game and video game sectors today, more 3D than 2D games are produced.