A Macintosh clone is a computer running the Mac OS operating system that was not produced by Apple Inc. The earliest Mac clones were based on emulators and reverse-engineered Macintosh ROMs. During Apple's short lived Mac OS 7 licensing program, authorized Mac clone makers were able to either purchase 100% compatible motherboards or build their own hardware using licensed Mac reference designs.
During Apple's switch to the Intel platform, many non-Apple Wintel/PC computers are technologically so similar to Mac computers that they are able to boot the Mac operating system using a varying combination of community-developed patches and hacks. Such a Wintel/PC computer running macOS is more commonly referred to as a Hackintosh. With Apple's transition to Apple silicon, making Mac clones may become considerably harder.