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Definition: macOS

The name of Apple's Unix-based operating system for Mac desktop and laptop computers. macOS is a continuation of the Mac OS X operating system, which was rebranded as macOS starting with the Sierra version in 2016.

Since its introduction in 1984, the Mac operating system has had five brand names (see below) and was designed to work with four hardware lines: Motorola, PowerPC, Intel and ARM. See Motorola, PowerPC, Intel Mac, Apple M series, macOS server and Mac computer.

Name Evolution
The Mac originally used "System" designations for its operating system, which then became "Mac OS." Starting in 1999, Mac OS X was a major upgrade that was branded with animal names followed by places in California (see Mac OS X).

  Year   Name      Version Name

  2023   macOS     14.0   Sonoma
  2022   macOS     13.0   Ventura
  2021   macOS     12.0   Monterey
  2020   macOS     11.0   Big Sur
  2019   macOS     10.15  Catalina
  2018   macOS     10.14  Mojave
  2017   macOS     10.13  High Sierra
  2016   macOS     10.12  Sierra

  2013   OS X      10.9 to 10.11

  1999   Mac OS X  10.0 to 10.8

  1995   Mac OS    7.6 to 9.2

  1984   System    1 to 7.5

Long Live the Mac Operating System
Introduced in 1999, Mac OS 8.6 was the first time the version number appeared on the Mac startup screen. Two years earlier, Mac OS 8.0 was the largest update to the Mac operating system since System 7.