IOS is Apple's proprietary mobile operating system (OS) for its handheld devices, such as the iPhone, iPad and iPod Touch. The operating system is based on the Macintosh OS X.
The IOS user interface is based upon direct manipulation, using multi-touch gestures. Interface control elements consist of sliders, switches, and buttons. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the iOS operating system and its multi-touch interface. Internal accelerometers are used by some applications to respond to shaking the device
iOS is the mobile operating system that runs on Apple’s mobile devices, i.e. iPhones and iPads. It’s the main software that allows you to interact with your Apple phone or tablet.
iOS is the first thing you see when you power up your device, in the form of your phone or tablet’s lock screen and desktops (which are filled with shortcuts to your favourite apps). When you head into your iPhone or iPad's settings menu, that’s also controlled by the operating system. From here you can adjust the device’s hardware settings, toggling features such as Bluetooth and WiFi on and off, or adjusting the brightness of the screen.