Bundles are a group of resources.
A bundle is a directory that has a well-defined structure and can host anything from classes to controllers and web resources. Even if bundles are very flexible, you should follow some best practices if you want to distribute them.
In ASP Net MVC, bundles are used to combine multiple javascript and CSS files into one, improving the download speed of a website.
In Android bundles are, "A mapping from String values to various Parcelable types." --http://developer.android.com/reference/android/os/Bundle.html Bundles are used to save the state of activities and/or fragments as well as passing data between classes.