Mac OS X Lion, or Mac OS X 10.7, is the eighth major release of the Mac OS X operating system released on 20 July 2011. It was announced on 20 October 2010 at Apple's Back to the Mac event. This version dropped support for the x86 userland and architecture and removed Rosetta and Front Row. It introduced the Launchpad and was originally only released as an App Store update that could only be updated normally from Snow Leopard.
It is the first version of Mac OS X to not be distributed on optical discs as it was released as an online-only download through the Mac App Store. Although, Apple would later release a USB flash drive containing the installation image in August 2011.
It is the last version to be released under the Mac OS X name as the operating system's branding was shortened to OS X starting with the release of OS X Mountain Lion in 2012. It is also the last version of Mac OS X to be released under the old release schedule in which every version of Mac OS X was released every two years as the operating system shifted to a new annual update schedule starting with the aforementioned version.