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Mac OS X

What is Mac OS X?

macOS (/ˌmækˈɛs/;[7] previously Mac OS X and later OS X) is a series of proprietary graphical operating systems developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple’s Mac computers. Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS, after Microsoft Windows.[8][9]

macOS is the direct successor to the classic Mac OS, the line of Macintosh operating systems with nine releases from 1984 to 1999. macOS adopted the Unix kernel and inherited technologies developed between 1985 and 1997 at NeXT, the company that Apple co-founder Steve Jobs created after leaving Apple in 1985. Releases from Mac OS X 10.5 Leopard[10] and thereafter are UNIX 03 certified.[11] Apple’s mobile operating system, iOS, has been considered a variant of macOS.[12]

The first desktop version, Mac OS X 10.0, was released in March 2001, with its first update, 10.1, arriving later that year. The “X” in Mac OS X and OS X is the Roman numeral for the number 10 and is pronounced as such. The X was a prominent part of the operating system’s brand identity and marketing in its early years, but gradually receded in prominence since the release of Snow Leopard in 2009. Apple began naming its releases after big cats, which lasted until OS X 10.8 Mountain Lion. Since OS X 10.9 Mavericks, releases have been named after locations in California.[13] Apple shortened the name to “OS X” in 2012 and then changed it to “macOS” in 2016, adopting the nomenclature that they were using for their other operating systems, iOS, watchOS, and tvOS. With Big Sur, Apple advanced the macOS major version number for the first time, changing it to 11 for Big Sur from the 10 used for all previous releases.

Wondering what the name of the latest macOS version is? Curious about the versions of Mac OS X that came before? Here we’ll fill you in on the names of the different versions of the Mac operating system: from the newest macOS to the first version of Mac OS X and the codenames that Apple used for them. We’ll also show you how you can check which version of macOS you are running and find out what the latest version of macOS is.

If you are wondering what the latest version of macOS is it’s Big Sur! And rather than version 10.16, it is version 11.

Mac OS X was first introduced almost 20 years ago in September 2000. With that anniversary coming up we have high hopes for the 20th anniversary version of the Mac operating system, but that’s in the future. In this article we are interested in the history of Mac OS X, or macOS as it is now known. 

For an overview of the features of the various versions of the Mac operating system, showing how it has developed over time, take a look at our video above. If you want to know the names Apple assigned to Mac OS X over the years, and the codenames that were used internally, read on.


List of macOS version names

Here’s an overview of every version of macOS and Mac OS X Apple has released. You’ll find a complete list of OS X version code names, along with internal code names (if available):

  • OS X 10 beta: Kodiak – 13 September 2000

  • OS X 10.0: Cheetah – 24 March 2001

  • OS X 10.1: Puma – 25 September 2001

  • OS X 10.2: Jaguar – 24 August 2002

  • OS X 10.3 Panther (Pinot) – 24 October 2003

  • OS X 10.4 Tiger (Merlot) – 29 April 2005

  • [OS X 10.4.4 Tiger (Chardonnay)]

  • OS X 10.5 Leopard (Chablis) – 26 October 2007

  • OS X 10.6 Snow Leopard – 28 August 2009

  • OS X 10.7 Lion (Barolo) – 20 July 2011

  • OS X 10.8 Mountain Lion (Zinfandel) – 25 July 2012

  • OS X 10.9 Mavericks (Cabernet) – 22 October 2013

  • OS X 10.10: Yosemite (Syrah) – 16 October 2014

  • OS X 10.11: El Capitan (Gala) – 30 September 2015

  • macOS 10.12: Sierra (Fuji) – 20 September 2016

  • macOS 10.13: High Sierra (Lobo) – 25 September 2017

  • macOS 10.14: Mojave (Liberty) – 24 September 2018

  • macOS 10.15: Catalina (Jazz) – 7 October 2019

  • macOS 11: Big Sur – 12 November 2020

The next version of macOS is likely to be macOS 12.