> But obviously it's for original RISC i.e. ARM.

Not sure if you actually mean that, but to me it sounds like you're implying that ARM is the "original RISC".

The first RISC processor was called RISC-I and came out of Berkeley research in 1981.

Around the same time came out the MIPS cpu, from Standford university, by a group who shortly after founded a company that by 1985 commercialized the first RISC CPU, the R2000.

ARM, SPARC and PA-RISC came out just about the same time.

The ideas were brewing for some time, but I think it's safe to say historically that the name "RISC" was not invented by ARM and that the R in ARM references a pre-existing term that has been developed at Berkeley.