A domain name is the unique name of a computer on the Web that distinguishes it from the other systems on the network.

They are sometimes colloquially (and incorrectly) referred to by marketers as "web addresses". Every website, e-mail account, etc, on the Internet is hosted on at least one computer (server). Each server has a unique IP address which is nothing but a set of numbers, such as "195.142.131.232" . To access a particular internet service, one can specify its IP address in an appropriate application, such as an FTP client; however because it is difficult to remember numbers, an IP address can be associated with a fully qualified host name (a domain name), such as "mambo-foundation.org".

Domain names also provide a persistent address for services when it is necessary to move to a different server, which would have a different IP address.These are the rules imposed by the way names are looked up ("resolved") by DNS. Translating numeric addresses to alphabetical ones, domain names allow Internet users to visit websites.