A Domain Name is attached to Domain Name System (DNS), which is a server enabled to translate numeric addresses (called IP, that is, Internet Protocol) into words. Each site, though they may appear in alphabetical letters, has a numeric IP address behind its name. This numeric address is the real address of the site on the internet.
The entire system is said to be hierarchial, but it is interesting to note that, there is no single registry for DNS information. When a user enters a domain name registration to their web browser, it is upto the DNS of that Uniform Resource Locator (URL) to handle the request. The DNS server then provides the browser which the correct IP. In case it doesn't exist, the server returns an error message or directs the user elsewhere.
A Domain Name is assigned to an IP address and this development has to be registered in the Name Server. The domain name has to be registered with the Network Information Centre (NIC), which is also called Domain Authority so as to preserve the database record of the domain ownership and the Name Servers that hold the domain's IPrecord.