A domain name is an address on the internet that is unique and it identifies the location of the site on the internet. There are a number of different endings, called extensions that aid in identifying the domain. The common extensions are .com, .net, .edu and .gov. There are also national identifiers; a domain name for a company in Great Britain could end in .uk.com. The domain name in St. Louis must meet certain requirements before it can take the extension, for example, only educational institutions can carry the .edu extension.