DNS Zone
A DNS zone is an administrative partition of the [[dns|DNS]] namespace that is managed by a single [[authoritative-dns|authoritative server]] or a coordinated group of servers. A zone is not the same as a domain: a domain owner can split their namespace into multiple zones using [[dns-delegation|delegation]], or a single zone can encompass several domains. Each zone is described by a [[zone-file|zone file]] starting with a mandatory [[soa-record|SOA record]] and contains all the DNS records the authoritative server is responsible for answering. Zone boundaries are defined by [[ns-record|NS record]] delegations to child nameservers.
Example
example.com and staging.example.com may live in separate DNS zones — the parent zone for example.com contains an NS record delegating staging to its own authoritative server, creating an independent zone boundary.