Nameserver

A nameserver is the machine that holds a domain's records and answers questions about them. Which nameservers speak for your domain is decided at the registrar, in the delegation stored by the registry, and every resolver on the internet follows that delegation before asking anything else. A domain normally lists two or more for redundancy.

The reason this matters when connecting a branded short domain is simple and it catches people constantly: your edits only count in the zone the current nameservers actually serve. A domain registered in one place but delegated to another — a hosting panel, a CDN, a corporate DNS service — ignores every record typed into the registrar's own editor, and the verification check keeps reporting that it cannot see your records. Look up the delegation first, then edit where it points.

Switching nameservers is a heavier operation than adding a record, because it replaces the entire record set at once. Copy the existing zone before you move it, mail and sender-authentication records included, or the domain will resolve while its email quietly stops.