Hierarchical namespace
The DNS hierarchical namespace is a map of how DNS servers determine what IP address to connect to given a URL
Registrars
Registrars, such as VeriSign, the operator of the .com and .net top-level domains, let any company, organization, or private individual register a TLD for any number of years. The domain name is then added to the Whois directory, and may point to a specific DNS server, which translates the domain name into an IP address.
Map
Domain names are read from right to left. Different sub-domains under a domain name are generally used to point to different servers, however, this is not always the case. For example, the Wikipedia community might want a Spanish version of the site to be on a server in Mexico. So, es.wikipedia.org might point to 67.167.39.4, while en.wikipedia.org and database.en.wikipedia.org can both point to 24.73.285.3, just different pages.
. -----------------------|----------------------------------- / / | \ \ \ com net mil org gov int | | | | | | google nsf army wikipedia whitehouse fr / | \ en es sv | database (imaginary)*