Domain Name vs Website
People new to Internet Marketing, as with any new enterprise, have a lot of new information to process. Much of it comes down to "in house" terminology.
An area that frequently causes confusion is the difference between a domain name and a website.
The way I think of it is
a) The domain name is like the address of a property eg 175 Main Street
b) The website is like the building that you find at that address. It could be a bungalow. Or a 3-bed semi. Or a 6 bed detached. Or a hotel. Or a block of flats. Or just an empty building plot.
The domain name is "registered" with the Domain Name Registrar. He keeps records of addresses. This is just like the Post Office having a record of 175 Main Street, and can send parcels to that address. But has no idea what kind of building exists there.
Likewise you could knock down the bungalow and replace it with a 3-bed semi. But the address does not change. It remains 175 Main Street.
Where does DNS come into this?
It tells the domain where to find the site. Like telling the Post Office where to find the building.