Everything "digital" or that is computer based.
The back end is where all the actual processing and work occur in the program. The user never sees or interacts with the back end, it is what the program has "under the hood". The front end is the...
Go to Menu>Settings>Applications>Manage Applications>[Name of App]>Force Stop (under the Controls subheading)
Yours faithfully Alfred E. Neuman (<your own name here)
if you want to know what the study is called it is geneology g-knee-olo-jee