CAD (Computer Aided Drafting) is, in general, a tool for computer based drafting. Screw the drafting boards and drafting pens and T-Squares! CAD is where it's at.

AutoCAD is just one particular breed, and in most industries, the most popular. Specifically, AutoCAD is a program created by AutoDesk (the makers of 3D Studio). It can handle everything from 2D drafting to 3D drafting. It can import/export to many popular 3d rendering programs such as 3D Studio Max/Vis, Form-Z, and (from what I have heard) Bryce 3D.

This program isn't the only of it's kind. It has competition: Microstation and QuickCAD are the biggest competitors. There are several others, including some Linux versions, but none compare to AutoCAD.

Autocad, a computer aided design tool, can be used for both mechanical and architectural drafting, either by itself or with a support program.

Architectural users may use the Architectural Desktop program to increase speed and accuracy. Mechanical users may use Mechanical Desktop in this same way.

Both are very useful programs for this field or work.
