Contacts The individuals responsible for a domain's function and management, as listed on the whois record.

Domain Name An alphanumeric name registered to an owner to point to email, web and other internet related services.

Nameservers The machines which direct domain names to the IPs and servers that make them function. There are 2 ways nameservers are used. Authoritative nameservers keep the records for a given domain name which are the final authority on where it resides. Local resolution nameservers are the machines that look for a domain name when you try to access it through your ISP.

Registrant The individual or company registering the domain, the domain's owner.

Registrar Company that handles the process of registering a domain name and maintains the whois record and rootserver entries for it. Usually the company the domain was purchased through.

Registry The company that maintains the definitive list of domains registered for all registrars to work with.

Root Servers The set of servers which keep the definitive record of what nameservers are responsible for what domains, as well as details of the domains' registration status, which is refered to by nameservers when looking up domain names.

TLD Top Level Domain, the final identifier in a domain name, eg. .com, .net, .org, .ca, .biz, .info. In some cases, most commonly country code domains, has 2 levels in it, such as .org.uk or .com.au.

Whois Record The file containing the ownership and contact information for a domain, as well as the nameservers authoritative for it. This record is maintained by the registrar of the domain, and filed with the root servers which are operated by the domain name registry.