CAD
Software for designing physical objects, where the file stores the steps that built the shape rather than just the surface.
CAD stands for computer-aided design, the software engineers and designers use to draw physical parts before anyone makes them. The important thing about a real CAD file is that it remembers intent. It does not just store a shape, it stores the operations that produced it: a cylinder of this diameter, a hole drilled here, an edge rounded there. That is why it is called parametric. Every one of those numbers is a parameter you can change, and the model rebuilds itself around the new value.
That is what separates CAD from a 3D scan. Scanning an object gives you a mesh, a shell of thousands of small triangles describing the surface. It looks correct and you can print it, but there is nothing to edit. Ask for the hole to be two millimetres wider and there is no hole in the file, only triangles arranged in a ring. Turning a mesh back into proper CAD is slow, skilled work, which is why AI tools that automate it are a big deal in manufacturing.