What does FQDN mean?
Fully Qualified Domain Name is more commonly known as its short acronym FQDN. Its main purpose is to show specifically the most complete version of the name of a particular domain name. In addition, that could be related to a website or to a server.
The Domain Name System (DNS) is decentralized, and it has a very precise hierarchical order. The beginning and above everything else is the Root, and a level below is the Top-Level Domain (TLD). Next in the hierarchical order is the domain, and lastly is the precise hostname.