The term Win32 is used in various contexts.
By Win32 a family of 32-bit Windows operating systems for the architecture x86 is understood.
When one speaks about a Win32-application, you should understand that one means a 32-bit program to be executed in the 32-bit environment and that has the ILP32 data model.
By Win32 a 32-bit API is also understood which is provided by the 32-bit Windows operating system.
There is a subsystem WoW64 on new 64-bit Windows systems to provide compatibility with obsolete 32-bit applications. The system translates the calls of the 32-bit API into the calls of the 64-bit API, redirects requests when working with the register and files and performs some other functions.
If you feel like the New Year just came, and you missed the first half of January, then all this ...