Three-dimensional (3-D) refers to objects that have depth, width, and height, making them appear more realistic than flat, two-dimensional (2-D) images. In 3-D, you can see the shape and volume of an object, allowing for a more immersive experience. This concept is widely used in various fields, including art, design, and animation. In technology, 3-D is often associated with 3-D modeling and 3-D printing, which create physical objects from digital designs. Movies and video games also utilize 3-D techniques to enhance visual effects, making scenes more engaging for viewers. Overall, 3-D plays a significant role in how we perceive and interact with the world around us.