A domain name looks like some-name.com, another-name.org or even yet_another.ca for example.

Those names are registered centrally for each "Top Level Domain" (TLD) such as .com , .org or .de ( "ca" being teh country code for Canada for example ).

Once a domain name is registered it can be used to locate servers on the internet by using the Domain Name System in order to route e-mail or access web sites.