Root

The root is the list that Top Level Domains exist within. The root exists above the Top Level Domains and defines a given name space by identifying the nameservers that will (should) answer authoratatively for a TLD.

ICANN, for example, manages the root on which the great majority of Internet traffic flows. It is possible to have more than one root and in fact some alternate root servers do exist, but have not gained much popularity to date.

The root that ICANN manages is centrally managed, but service of the root zone file is provided by a series of geographically and operationally diverse root servers.