iOS (originally iPhone OS) is a mobile operating system created and developed by Apple Inc. and distributed exclusively for Apple hardware. It is the operating system that presently powers many of the company's mobile devices, including the iPhone, iPad, and iPod touch. In October 2015, it was the most commonly used mobile operating system, in a few countries, such as in Canada, the United States, the United Kingdom, Norway, Sweden, Denmark, Japan, and Australia, while iOS is far behind Google's Android globally; iOS had a 19.7% share of the smartphone mobile operating system units shipped in the fourth quarter of 2014, behind Android with 76.6%. However, on tablets, iOS is the most commonly used tablet operating system in the world, while it has lost majority in many countries (e.g. the Africa continent and briefly lost Asia).
For More: iOS