I've been following UAE for a long time, even prior to the WinUAE version. The original UAE page at one time (a very long time ago) stated that UAE stood for Unix Amiga Emulator. When the application started getting ported to other platforms, the original UAE site had a comment that due to the number of platforms it had been ported to, it should probably be changed to Universal Amiga Emulator. This was back when the original Unix version of UAE was still in development, and when WinUAE was not THE primary port.