Crossover is a software that allows Windows applications to be run on Mac systems without requiring virtualization, dual booting, or Wine. It installs and runs programs inside "bottles" that emulate Windows environments. While it does not provide a perfect experience and some bugs exist, Crossover makes many common Windows programs like Microsoft Office and Visio usable on Mac with acceptable performance for a one-time fee. Limitations include the need for separate Windows licenses and lack of support for Active Directory integration features.