macOS is a proprietary Unix operating system, derived from OPENSTEP for Mach and FreeBSD, which has been marketed and developed by Apple since 2001. It is the current operating system for Apple's Mac computers. Within the market of desktop and laptop computers, it is currently the second most widely used desktop OS, after Microsoft Windows and ahead of all Linux distributions, including ChromeOS and SteamOS. As of 2026, the most recent release of macOS is macOS 26 Tahoe, the 22nd major version of macOS.