3D /ˌθriː ˈdiː/ [uncountable]

(also three-D or 3-D)

the quality of having, or appearing to have, length/height, width/breadth and depth or the illusion of depth (= three dimensions) and hence much more real; lifelike:

“a three-D image” “These glasses allow you to see the film in 3-D.”

3-D is both a noun and an adjective:

“a 3-D film” “a film in 3-D”

It is short for ‘three dimensional’ /ˌθriːdɪˈmenʃənəl/.

A box is three-dimensional; it is solid, and not thin like a piece of paper. It has volume, a top and bottom, left and right (sides), as well as a front and back. You can turn the box around to view it from another side (called a face, surface or simply side). A dimension is measurable in inches, microns, miles, kilometers, or any other unit of length. The three dimensions are often called length (or depth), width (or breadth), and height. Some purposes use other words.

3D graphics are used to make video games or animated movies. Many calculations are needed to make pictures seem three-dimensional on a screen. Modern computers usually have a GPU (Graphics Processing Unit) to handle these calculations.

In mathematics, length, width, and height are given in letters (variables) to make them easier to write, or if a value is not known. Often X is width, Y is height, and Z is length. The mathematical study of 3D shapes and dimensions is called solid geometry.

Some people see time as a fourth dimension. It is also measured. It is measured in units of time such as seconds, hours, years, or any other measurement of time.


  • Research Questions:
  1. What are these the dimensions in 3-D?
  2. What’s 2D?
  3. How many dimensions are there in all?
  4. Are there 1D, 4D, 5D, etc.?
  5. What things are described specifically as 3-dimensional?