Fully Qualified Domain Name (FQDN)
Definition - What does Fully Qualified Domain Name (FQDN) mean?
A fully qualified domain name (FQDN) is a domain name that specifies not only its top-level domain and parent domain name, but also its local host. These more specific domain names reveal additional information about the origin of a Web page in the actual uniform resource locater (URL).
Techopedia explains Fully Qualified Domain Name (FQDN)
One issue with a fully qualified domain name involves the resolution of these domain entries. Organizations like the Internet Engineering Task Force have identified specific resolution processes for fully qualified domain names in order to help establish consistent communications.