InterNIC was the only major nodal point for the whole Internet until recently. It owned and managed the primary DNS server. Was owned by Verisign formerly Network Solutions.
Now obsoleted by ICANN (http://www.icann.org). Some would say that things haven't really changed.
Internic is a now defunct entity replaced by ICANN (the Internet Corporation for Assigned Names and Numbers). The people who oversee the mostly privatized domain name industry and oversee the assignment of IP dotted quad addresses and domain names ending in .com .net .info .biz and .org. They don't handle .gov, .mil or .ca. Their job is to make sure no two people have the same domain name or IP. A good resource to check if a given domain name has already been taken, find out who owns any given domain, or register a domain name is http://www.Nic.net . The site is very busy because of the speculation fad buying and selling domain names.