A piece of code with a well-defined life cycle e.g. Activity, Receiver, Service, etc, is what an android component can be simply understood as. Activities.

Activity:

Being similar to a Frame in AWT, an activity as a class represents a single screen. It is a core building block, i.e., the fundamental component of android.

The UI element including button, label, text field, etc, and anything that one can see is a view.

Service:

Being a background process the service can run for a long time.

The local and remote are the two types of services. Within the application, the local service is accessed. While from other applications running on the same device the remote service can be accessed remotely