What do you call your main controller?

I'm making a very simple social network, just as an exercise.  I haven't got a name for it, so for this example, lets just call it poo.com.

So if I'm on poo.com the url will look something like www.poo.com/index.php/controller/home

Something like this would be better www.poo.com/index.php/home

I know I could have a controller called "home", and just use the index function but I don't want to use a different controller for every single function. That would make writing the code a nightmare.

Any suggestions? What do you call your main controller? From what I've been reading there are probably ways to get rid of the controller from the url, but even so, I still have to call the controller something.