
Starting with Mac OS X 10.7 Lion, macOS Server is no longer offered as a separate operating system instead, server management tools are available for purchase as an add-on. Starting with the Intel build of Mac OS X 10.5 Leopard, most releases have been certified as Unix systems conforming to the Single Unix Specification.


Lion was sometimes referred to by Apple as "Mac OS X Lion" and sometimes referred to as "OS X Lion", without the "Mac" Mountain Lion was consistently referred to as just "OS X Mountain Lion", with the "Mac" being completely dropped.

The operating system was further renamed to "macOS" starting with macOS Sierra. MacOS retained the major version number 10 throughout its development history until the release of macOS 11 Big Sur in 2020 releases of macOS have also been named after big cats (versions 10.0–10.8) or locations in California (10.9–present).Ī new macOS, Monterey, was announced during WWDC on June 7, 2021.Ī diagram of the relationships between Unix systems including the ancestors of macOSĪfter Apple removed Steve Jobs from management in 1985, he left the company and attempted to create the "next big thing", with funding from Ross Perot and himself.
