1. A robot with a human appearance. Android OS is a Linux-based operating system designed primarily for touch-screen mobile devices such as smart-phones and tablet computers.
2.  Android is an open source code and permissive licensing allows the software to be freely modified and distributed by device manufacturers, wireless carriers and enthusiast developers. Additionally, Android has a large community of developers writing applications that extend the functionality of devices, written primarily in a customized version of the Java programming language.
3.  Androids user interface is based on direct manipulation, using touch inputs that loosely correspond to real-world actions, like swiping, tapping, pinching and reverse pinching to manipulate on-screen objects.That’s why thedevices arecalled smart!
4.  Internalhardware such as accelerometers, gyroscopes and proximity sensors are used by some applications, for example adjusting the screen from portrait to landscape or allowing the user to steer a vehicle in a racing game by rotating the device, simulating control of a steering wheel.
5.  Android has a growing selection of applications, which can be acquired by users either through an app store such as Google Play or by downloading and installing the applications APK (Android file format) file from a third-party site.
6. Android applications run in a sandbox, an isolated area of the system that does not have access to the rest of the systems resources, unless access permissions are explicitly granted by the user when the application is installed. Before installing an application, the Play Store displays all required permissions: a game may need to save data to an SD card, for example, but should not need to read SMS messages. After reviewing these permissions, the user can choose to accept or refuse them, installing the application only if they accept.
7.  Google provides major updates, incremental in nature, to Android every six to nine months, which most devices are capable of receiving online.
8.  Android updates are always named after a sweet thing, the names of all the updates are: cup cake, donut, éclair, froyo (frozen yoghurt dessert), gingerbread, honeycomb, ice-cream sandwich and (the latest) jellybean.