iOS is Apple's mobile operating system. Originally developed for the iPhone, it has since been extended to support other Apple devices such as the iPod touch, iPad and Apple TV. iOS is derived from Mac OS X, with which it shares the Darwin foundation, and is therefore a Unix-like operating system by nature. The user interface of iOS is based on the concept of direct manipulation, using multi-touch gestures.
You can learn all about iOS 7.0 here.