Specific and general acid catalysis
I have wondered about this too. Although I could be wrong it is reasonable to assume (or at least handy to keep as a reminder) that the term "special" refers to the fact that compound is protonated in a very specific state, namely before the actual reaction occurs. General acid catalysis can happen both before the reaction or at any time during the reaction (i.e. in some transition state), whatever is likely in some range around the pH of the acid. Hence it is more general version of the special case mentioned above.