The second season of Code Geass: Lelouch of the Rebellion is suffixed with R2. C.C's and V.V's names, while written with the dot between them they are pronounced as C2 and V2.

So I am wondering what the R2 in the title means: is it similar to how C.C's and V.V's names are writen and pronounced and it's supposed to be written as R.R? Does it mean something?