When I upgrade my iPhone, can I upgrade to the same phone?

I have the iPhone 4S and my upgrade is soon, but I don't want the iPhone 5. And I have some little cracks and my speakers are weird. So when my upgrade comes can I just get the same phone that I have now?

NO

what does the upgrade means

it means to have the latest TECHNOLOGY and to chage the older thing with the new best one

I don't see why not. It's called an "upgrade" since the expectation is that you'll get a newer phone, but it's really just an opportunity to buy a new phone at a subsidized cost.

Sure, you can upgrade to any phone you want, even the same model. You can then keep or even sell your old phone.