not in ohio
Well, it depends: "PC" as "personal computer" can be any instruction set and any architecture (*). My first personal computer was a VAX.
On the other hand, "PC" is also construed as "the IBM PC", which has come to describe a particular (evolving) architecture based on the x86 instruction set, address space split between RAM and IO, BIOS calls using INT, etc. These days we sometimes call that "Wintel" rather than "IBM". Whatever - the thing needs a name so we can talk about it.
(*) a system architecture and an instruction set are separate concerns. One can conceive of an x86 system that does not use the "PC" architecture, e.g. no BIOS, or no real-mem hole at 640K, etc.