Android is a software stack for mobile devices that includes an operating system, middleware and key applications. The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language.
Android is a mobile operating system initially developed by Android Inc. Android was purchased by Google in 2005.[4] Android is based upon a modified version of the Linux kernel. Google and other members of the Open Handset Alliance collaborated to develop and release Android to the world.[5][6] The Android Open Source Project (AOSP) is tasked with the maintenance and further development of Android.[7] Unit sales for Android OS smartphones ranked first among all smartphone OS handsets sold in the U.S. in the second and third quarters of 2010,[8][9][10] with a third quarter market share of 43.6%.

Android is the name of the software that an increasing number of today’s phones run on. It’s developed by Google and comes with a range of Google features, most notably Search and Maps, installed as standard.

Google makes the software not the hardware. One phone – the Google Nexus One – is branded as “the Google Phone” but is actually made by HTC, who make other Android phones such as the HTC Desire and HTC Legend. It is considered to be the flagship Android phone, even though some Android phones have bigger screens and better cameras.

Of all of the Android phones, the Google Nexus One is currently always the first to receive new Android updates.

The latest such “Google Phone” to be announced is the Google Nexus S, which is made by Samsung.