A 32-bit version of Windows. Many editions of Windows have come in both 32-bit and 64-bit versions. See 32-bit computing
Win32 is the programming interface (API) for 32-bit and 64-bit Windows operating systems. Starting with Windows 95, developers write applications that call the routines in the Win32 API. With Windows 8, the WinRT programming interface was used for tablet-style apps.
An application written to Win32 can run in all Windows versions except Windows RT on ARM tablets. In addition, special routines in server versions of Windows may not run in Windows clients. See Win RT
API Can Run in Windows
WinRT Windows 8, Windows RT
Win32 95/98, NT, 2000, XP, 7, 8 and 10
Win32s Win32 + 3.1
Win16 3.x, 95/98, NT, 2000, XP