> The Xbox One has been emulated though (well not emulated, it's a compatibility layer like Wine).

The parenthetical is not needed. It is OK to call Wine an emulator. The "Wine Is Not an Emulator" thing came about later and was essentially a marketing change. How it came about is interesting.

The first suggestion to change the meaning of the word from a shortening of "windows emulator to the not an emulator backronym was in 1993 over concern that "windows emulator" might run into problems with Microsoft trademarks, but no action was taken.

Over time the not an emulator usage became an accepted alternative. The Wine FAQ in late 1997 for example said:

  The word Wine stands for one of two things: WINdows
  Emulator, or Wine Is Not an Emulator. Both are right.
  Use whichever one you like best.

The release notes stopped calling it an emulator at the end of 1998. The 981108 release notes said:

  This is release 981108 of Wine, the MS Windows emulator.

The 981211 release notes said:

  This is release 981211 of Wine, a free implementation of
  Windows on Unix.

As far as I have been able to tell from my recollections of that time and what I was able to find when I looked into it later is that this happened for two reasons.

1. Wine was useful for more than just running Windows binaries on Unix. It could also be used as a library you could link with code compiled on Unix as an aide to porting Windows programs to Unix.

2. Hardware emulators that emulator old systems like GameBoy or Apple II had become popular. Many people were only familiar with that kind of emulator, and those (the emulators, not the people!) tended to be slow.

That was fine when your emulator is running on a machine with a clock speed 300x that of the machine you are emulating and that has a much more efficient CPU, but when you tried to use a hardware emulator for something comparable to your machine it was usually unbearably slow.

People only familiar with such hardware emulators might see Wine described as a Windows emulator and think it was doing hardware emulation and not even give it a try. By dropping calling it an emulator Wine sidestepped that problem.