Three-dimensional (3D) refers to objects that have width, height, and depth, allowing them to occupy space. Unlike two-dimensional (2D) shapes, which only have length and width, 3D objects can be viewed from multiple angles. Common examples of 3D objects include cubes, spheres, and pyramids. In technology, 3D is often used in graphics and modeling, allowing for realistic representations of objects in video games, movies, and virtual reality. 3D printing is another application, where digital designs are transformed into physical objects layer by layer, showcasing the versatility of three-dimensional design in various fields.