A Hackintosh is a PC which can run MacOS and in some cases also be used as a multi-OS system such as a dual-boot Windows / Mac system. It is a computer which for all practical purposes works like an Apple computer (Macintosh), but is built of hardware different from a Mac, and hence is called a Hack-intosh.
These PCs are popular with creative folks like video editors and audio producers who need a high end PC which supports MacOS based tools.
Hackintoshes offer various advantages vs a regular Mac in terms of performance, upgrade-ability, multiple OS setup, aesthetics, modularity and others. It used to be considered risky to deal with any kind of update / software issues, but these issues have been addressed with stable ‘Vanilla Hackintosh’ configs which even allow for storage devices to be moved freely between Macs and Hackintoshes without any issues.