Comment by unscaled

There's also no official x64, x86-64 or i686 "architecture", if we want to be pedantic.

There is no official name for the 64-bit instruction set for the x86 architecture, as far as I know. As far as I remember, AMD called this ISA "AMD64" when it was released and Intel just called it "Intel 64". Of course, this term only refers to the basic instruction set. If you see an x86-64 binary, it may be compiled with an extended instruction set like SEE4 or AVX that is not necessarily supported by every x86-64 CPU out there.

Even the umbrella term "x86" for the 32-bit ISA was retconned as far as I know: Intel did not use that term originally.