Sorry, this whole letter thing seems absurd to 
me.  I say CG because people recognize it a lot 
faster.  Most movies use the term CG(I), so the 
vast public just hears and it and automatically 
knows what it means.  I mean really guys, you see 
the douga and genga out there...you know these 
anime series coming out arent all CGI.  Where's 
the confusing part?  Using this abbreviation is 
just commonplace, people use it to describe many 
different mediums assisted by computers.  If 
someone is actually, and I mean really perplexed 
by this, I suggest they seek ways to clear their 
mind a bit better.  99% of all animation, 2d that 
is, is all done on paper first.  I recently went 
to Siggrapn in Texas a couple weeks ago.  The 
movie Spirit: Stallion of the Cimarron was all CG 
colored, and in a lot of cases there was a lot of 
3d implemented.  BUT, the real animation was all 
done by hand, on paper...I saw the sheets with my 
own eyes.  So, keep that in mind.  2D = paper, 3D 
= all CGI.  When you hear the term CGI  in 
reference to 2D, just assume they mean the 
coloring, it's that simple.