A widget is an app that lives on your Android device’s home screen and provides information (calendar, email inboxes) without you having to open it separately.
Note: Widgets have been available for years now but became more popular with the introduction of Jelly Bean in 2011 when they were re-designed and given a refreshed look so as to make them easier to use. They can be accessed by dragging down from anywhere across the top of your phone’s screen.
Android widgets can be grouped into four different types; information widgets, collection widgets, control widgets and hybrid widget. The Android framework provides a set of tools for developers to create this type of widget.