What Does CAD Mean? What Advantage Can Be Had In Using CAD?

CAD means Compute Aided Design
The use is to draw the articles in all the shapes and all the views, that means in 3d angle we can view through CAD
It is completely for the mechanical branch and fully designed in computer programming. Using this software we can design so many things.

Yes, CAD means Computer Aided Design, or sometimes Drafting.  There are two main types of CAD - 2D and 3D.  Either one is used to draw something.  The purpose may be to figure out how to make something fit together, or it might be to communicate the way something is made.   Drawings are 2D (like a pencil and paper picture), but in 3D CAD you make a 3D model of an object  that you can look at from any angle.    With either type, some advantages, as compared to pencil & paper, are:
- accuracy (computer lines are straight , circles round, dimensions exact)
- clarity (you can 'zoom in', enhance detail, use typed text)
- neatness (the "line" command works the same for everybody, and so does the "erase" command)
- speed (copy from other CAD work & modify)
- for 3D especially, the CAD model can serve as a prototype, since you create virtual 3D objects in the software. You can fit things together, spin them around to view from all sides, cut sections to see inside, even get strength and weight information.  You get a lot of the advantages of seeing how it would look when it is made, without the expense of the manufacturing.