FAQ on Domain Names by changefrom.com

You should check the domain name you would like to register. If the second-level domain name (YourName.com, NOT www.YourName.com) you want is already in InterNIC' database, your query will return a listing including information about the organization that holds the name. If it is not in the database the answer returned will be: No match for ... Who is InterNIC? InterNIC is the only organization that maintains the database of information related to a domain name under .com, .net, .org, and .edu. Registrations, renewals, and modifications to any of the information on the Whois database have to be processed through them.

What does "Whois" refer to?
A searchable database maintained by InterNIC, which contains information about networks, networking organizations, domain names, and the contacts associated with them for the com, org, net, edu, and ISO 3166 country code top level domains. Also, the protocol, or set of rules, that describes the application used to access the database. Other organizations have implemented the Whois protocol and maintain separate and distinct Whois databases for their respective domains.