a part of your domain name but it may contain different DNS information
omain ame ystem zone A part of the DNS namespace that consists of a single domain or a domain and subdomains managed as a single, separate entity.
A zone in the Domain Name System (DNS) is a subdivision of the entire DNS namespace. A particular DNS server has authority to resolve DNS queries for DNS zone.
A DNS zone is a portion of the global DNS namespace. This namespace is defined by the DNS protocol (RFC xxxx) and is laid out in a tree structure from right to left, such that divisions of the namespace are performed by prepending a series of characters followed by period ('.'), to the upper namespace (e.g. 'com.' to 'wikipedia.com.').