Based on OS X, iOS is an operating system for mobile devices developed by Apple, initially created for the iPhone. (The original name for the operating system was “iPhone OS.”) The iOS is now used in a variety of Apple mobile devices, including various generations of iPhone, iPod touch, iPad, and Apple TV.
The iOS supports third-party applications, and its user interface supports multi-touch gestures, such as tap, swipe, pinch, reverse pinch, and more. iOS is space efficient, requiring just 74MB of storage.