“3D” stands for three-dimensional.

It refers to something that has three dimensions: length, width, and depth.

Examples:

• 3D objects: cubes, spheres, real-world objects
• 3D graphics: computer models that appear to have depth (used in movies, games, animation)
• 3D printing: creating physical objects layer by layer
• 3D space: the real world we live in

In short, 3D = something that has depth and looks or exists as a solid object rather than flat.