To register a domain name, you will be asked to provide the registrar you select with the various contact and technical information that makes up the registration. The registrar will then keep records of the contact information and submit the technical information to a central directory known as the "registry." This registry provides other computers on the Internet the information necessary to send you e-mail or to find your web site.

I was told I need a Registry for my domain name, but i dont know what a "registry" is