A smartphone operating system (OS) and software platform created by Google. Android is based on Linux.
Multiple manufacturers make phones that run Android. As a software platform, Android allows apps (software) written for Android to run on all Android-based phones, regardless of manufacturer.
Besides app compatibility, Android has a specific user interface. This means all Android phones work in a somewhat similar way; learning to use one Android phone will make using other Android phones familiar. However, Android permits greater customization (by carriers and manufacturers) than most other platforms, so there can still be significant interface differences between various Android-based phones.
Android competes with Apple's iOS, Microsoft's Windows Phone, and other smartphone platforms.
"Android" should not be used interchangeably with "Droid", which is a Verizon Wireless brand of some of its Android-based phones.