> CGI - As Bill stated means Computer Generated 
Imaging 

I would say : Common Gateway Interface... 
(especialy when discussing on the web)

> The term is also used when computers are used
> to generate a crowd of people or animals in a
> 2D animated movie or show some 3D object

Randering ? So CR ? (computer randered)

CAA ? Computer Assisted Animation (humm...) ? :)