Thanks a lot! > Based on that definition, a host cannot be a subdomain, only a domain can be a subdomain. A subdomain will also have a separate zone file with

Thanks a lot! > Based on that definition, a host cannot be a subdomain, only a domain can be a subdomain. A subdomain will also have a separate zone file with a SOA record (Start of Authority). That would seemingly confirm my line of argument that e.g. "www" is not a (sub-)domain but "just" a hostname. Now if "www" was an NS record and pointed to a nameserver with its own SOA record, then that would be a sub-domain of course, but of course I was only referring to A and CNAME records. > Is "shop" both a host AND a subdomain in that case? AFAIK, having NS records won't allow you to define additional records, hence that shop A record could only be part of the shop domain as part of the naked domain. In that case I'd say "shop" is just as much a domain as "example.com".