Sounds like an attempt at phrasing for the general public. Android apps have zero or more activities, each of which may be thought of as a single screen and a

Sounds like an attempt at phrasing for the general public. Android apps have zero or more activities, each of which may be thought of as a single screen and a single Intent, which is a bit like a URL (and sometimes very much like a URL). A messenger or email app will typically have a main activity, an activity to view a single message, an activity to view a conversation with someone, perhaps an activity to view a single attached image, probably an activity to view and edit the application's settings, and so on. What is sent is perhaps the app's name and a class name within the app for each activity that's started.