Marking x86 is a nomenclature and not a physical quantity?

Question

Processors

Why were 32 bit processors written as x86 and 64 bit processors began to be written as x64, respectively bits?

Answer 1

https://ru.wikipedia.org/wiki/X86

Answer 2

X86 is the instruction set of 32-bit Intel processors. X64 is an instruction set originally invented by AMD and later licensed by Intel. As a result, we can also meet the description of amd64. But all this applies only to intel and amd processors, in the usual sense. There are spark64, and mips64, and even arm64 and ppc64, which have nothing to do with them.