Stands for "Computer-Aided Design." Also known by engineers and architects as the best invention of all time. Today, CAD software is used for nearly all three-dimensional designing. Designers can turn an object into an electronic representation more quickly and accurately than by diagraming it with a pencil and paper. Better yet, objects created with CAD software can be moved, resized, and rotated instantly. With a pencil and paper, you can only erase so much before it starts to smudge.