WOW

Short for Win16 on Win32, a collection of programs in Windows NT and later operating systems that allows 16-bit applications to run in a 32-bit Windows environment through a process called thunking. Without WOW, Win32 programs cannot communicate with Win16 programs, though the ability to do so is often necessary with legacy systems or when systems use 16-bit applications with newer 32-bit operating systems. WOW is designed to make the differences between 16-bit and 32-bit applications invisible to the user.