Such can be obtained from large ISP's, though. The DNS enables users to enter words or names instead of numbers. In other words, a domain name is something like an Internet address.
Domain names have a hierarchical structure.
See this page to find links to other registration agencies. See this list to find organisations registering domain names with other extensions. It is accessible to the general public. A domain name must be unique. If a registered domain name has to be changed for some reason, the old one has to be deleted first, followed by registering the new one.