Zone

In the Domain Name System, a zone may be either an entire domain or a domain with one or more subdomains. A zone is a configurable entity within a name server under which information on all Internet resources pertaining to a domain and a selected set of subdomains is described. Thus, zones are administrative building blocks of the DNS name space just as domains are the structural building blocks. As a result, the term "zone" commonly is used even to refer to a domain that is managed as a standalone administrative entity (e.g., the root zone, the .com zone).