Domain Name System (DNS)
A model for tracking other machines (that contain web sites) and their numeric IP addresses.
It translates domain names (for example, www.duszahosting.com into a numerical IP address). When a computer is referred to by name, a domain name server puts that name into the numeric IP address assigned to that computer.
So when you buy a domain, say www.yourname.com, it does not become accessible until it gets assigned an IP address from a hosting company. Once the IP address is assigned, a cross-reference record (DNS record) is created that points your domain name to the numeric IP address.