Mac OS X Lion

Mac OS X Lion (version 10.7; marketed as OS X Lion) is the eighth and current major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers.
A preview of Lion was publicly unveiled at Apple's "Back to the Mac" event on October 20, 2010. It brings many developments made in Apple's iOS, such as an easily navigable display of installed applications, to the Mac, and includes support for the Mac App Store, as introduced in Mac OS X Snow Leopard version 10.6.6. On February 24, 2011, the first developer's preview of Lion (11A390) was released to subscribers of Apple's developers program. Other developer previews were subsequently released, with Lion Preview 4 (11A480b) being released at WWDC 2011.
Lion achieved golden master status on July 1, 2011, followed by its final release via the Mac App Store on July 20, 2011. Apple reported over 1 million Lion sales on the first day of its release. As of October 2011, Mac OS X Lion has sold over 6 million copies worldwide.

Mac OS X v10.7 "Lion"
Part of the Mac OS X family
Screenshot of Mac OS X Lion
Developer
Apple Inc.
Website	Official website
Releases
Release date	July 20, 2011; 3 months ago
Current version	10.7.2 (11C74) (October 12, 2011; 17 days ago)
Source model	Closed source (with open source components)
License	APSL and Apple EULA
Kernel type	Hybrid
Update method	Apple Software Update
Platform support	x86-64
Preceded by	Mac OS X v10.6 "Snow Leopard"
Support status
Supported Hardware support The first developer preview of Lion added TRIM support for SSDs shipped with Macs, which is also included in the latest version of Snow Leopard (10.6.8) shipping with current MacBook Pros before July 20, 2011. As of yet, there is no TRIM support for other SSDs.  System requirements x86-64 CPU (Macs with an Intel Core 2 Duo, Intel Core i3, Intel Core i5, Intel Core i7, or Xeon processor.) At least 2GB of RAM Mac OS X 10.6.6 or later (Mac OS X 10.6.8 is recommended) 7 GB of free hard drive space is recommended AirDrop is supported on the following Mac models: MacBook Pro (late 2008 or newer), MacBook Air (late 2010 or newer), MacBook (late 2008 or newer), iMac (early 2009 or newer), Mac mini (mid 2010 or newer), Mac Pro (early 2009 with AirPort Extreme card and mid 2010 or newer).