First, "WIN10.PRO" obviously refers to Windows 10 Professional. "AIO" stands for "All-in-One", which I know means the ISO image contains multiple versions of Windows, probably for different use cases like Home, Pro, Enterprise, etc. "U18" could be a build number. "X64" is the architecture, so it's for 64-bit versions. "-WPE-" likely stands for Windows PE, which is the Windows Preinstallation Environment, used for deployment or recovery tasks. The ".ISO" is the file format, a disc image typically used for creating bootable media.