Wine is an open-source project, which implements the Windows API on top of the Unix/Linux operating system family. It works by translating Windows API calls into POSIX calls on-the-fly. In practice, this means you can run Windows applications on Macs, BSD Unix, and desktop Linux.
This latest version has two new major features. The first is that Microsoft Office 2013 is now supported. The other is that Wine will now run on 64-bit macOS.
How to install Microsoft Office 2010 on Linux with CrossOver (Gallery)
It includes many other improvements. It doesn't, however, have all the changes that its developers had hoped for. Features that have been deferred to the next development cycle are the Direct3D command stream, the full Human Interface Device (HID) support, the Android graphics driver, and message-mode pipes.
So, if your job requires you, for example, to run Office 2013 instead of LibreOffice on your Mac or Linux desktop, try Wine. I've been using its earlier versions for over 20 years and it continues to work well.