https://wiki.winehq.org/FAQ#Is_Wine_an_emulator.3F_There_seems_to_be_disagreement
1.3 Is Wine an emulator? There seems to be disagreement
There is a lot of confusion about this, particularly caused by people getting
Wine's name wrong and calling it WINdows Emulator.
When users think of an emulator, they tend to think of things like game console
emulators or virtualization software. However, Wine is a compatibility layer -
it runs Windows applications in much the same way Windows does. There is no
inherent loss of speed due to "emulation" when using Wine, nor is there a need to open Wine before running your application.
That said, Wine can be thought of as a Windows emulator in much the same way that
Windows Vista can be thought of as a Windows XP emulator: both allow you to run
the same applications by translating system calls in much the same way. Setting
Wine to mimic Windows XP is not much different from setting Vista to launch an application in XP compatibility mode.
A few things make Wine more than just an emulator:
Sections of Wine can be used on Windows. Some virtual machines use Wine's
OpenGL-based implementation of Direct3D on Windows rather than truly emulate 3D hardware.
Winelib can be used for porting Windows application source code to other operating
systems that Wine supports to run on any processor, even processors that Windows itself does not support.
"Wine is not just an emulator" is more accurate. Thinking of Wine as just an
emulator is really forgetting about the other things it is. Wine's "emulator" is really
just a binary loader that allows Windows applications to interface with the Wine API replacement.
