Knowledge Is Power

  The green robot is the Android symbol

Definition: Android is a smartphone operating system (OS) developed by Google. It is used by a variety of mobile phone manufacturers including Motorola, HTC and Sony Ericsson.
The first phone to run on the Android OS was the HTC Dream which was launched on 22 October 2008. Google's own-brand Android phone, the HTC-made Nexus One, was launched in the US on 5 January 2010.
At present there are four main varieties of the Android OS available:

• Android 1.5 (aka 'Cupcake')
• Android 1.6 (aka 'Donut')
• Android 2.0/2.1 (aka 'Eclair')
• Android 2.2 (aka FroYo)

Each version features slightly different functionality and user interface, and recently-launched software may or may not work on older versions of the OS.
Android is an open-source operating system which means that any manufacturer can use it in their phones free of charge.