Android is a mobile operating system developed by Google based on Linux kernel, which is mainly designed for touch-screen mobile devices such as smartphones and tablets. Android's user interface is mainly based on direct operation, using touch gestures roughly corresponding to real-world actions (such as swipe, tap and knead) to manipulate objects on the screen, as well as virtual keyboard for text input. In addition to touch-screen devices, Google has further developed Android TV for TV, Android auto for cars and Android wear for watches, each with a dedicated user interface. Android variants are also used in laptops, game consoles, digital cameras and other electronic devices.

Android was originally developed by Android Inc., which Google Inc. acquired in 2005, and established in 2007 with the Open Handset Alliance, which is composed of hardware, software and telecom companies dedicated to promoting open standards for mobile devices. Since the first commercial Android device in September 2008, the operating system has experienced several major versions. The current version is 7.0 "nougat", which was released in August 2016. You can download Android apps ("apps") from Google play. Store, with over 2.7 million apps as of February 2017. Android has been the best-selling operating system on tablets since 2013 and runs on most smartphones. In September 2015, Android had 1.4 billion active users per month and had the largest installation of all operating systems.

Android's source code is released by Google under an open source license, although most Android devices end up with a combination of free and open source and proprietary software, including the proprietary software needed to access Google's services. Android is popular with technology companies that need high-tech devices off the shelf, low-cost and customizable operating systems. Its openness encourages developers and enthusiasts to use open source code as the basis of community driven projects, which provide updates for older devices, add new functions for advanced users, or introduce Android into the device operating system attached to other devices. Extensive hardware changes in Android devices can cause significant delays in software upgrades. New versions of the operating system and security patches usually take months to reach consumers, sometimes not at all. Android's success has made it the target of patent and copyright litigation, part of a so-called "smartphone war" between technology companies.