What is FQDN (Fully Qualified Domain Name)
The FQDN stands for the longer Fully Qualified Domain Name. It is exactly what it says, the most full way to write a particular domain name (website or a server). As you know, DNS is a hierarchy system, starting from the root, then TLD, then the domain, and last is the particular hostname.
Syntax of a fully qualified domain name: hostname.domainname.TLD ([hostname].[domain].[tld].)
Example of fully qualified domain names: mail.google.com, ftp.microsoft.com, movies.disney.com