RFC 1034:DOMAIN NAMES - CONCEPTS AND FACILITIES
RFC-Ref

root domain


Click on the red underlined text to get to the source

... In this example, the root domain has three immediate subdomains: MIL, EDU, and ARPA. The LCS.MIT ...


... class, and would have zones for these domains. The zone data for the root domain might be: ...



Google
Web
RFC-Ref