Definition – What does FQDN mean?
Fully Qualified Domain Name is a domain name that includes a hostname. i.e., the URL www.glossaryweb.com is an FQDN since it contains a hostname www and a domain glossaryweb.com. The domain name glossaryweb.com is not fully capable because it does not include a hostname. A Fully Qualified Domain Name can be broken down into three parts such as Hostname, Domain and Top-level domain (TLD). An official domain name has the format [hostname]. [domain]. [tld], the hostname can be used to specify services for a single domain.
Glossary Web explains FQDN
Subdomains can also be used as a website addresses are also fully capable domain names. i.e., CNET uses the www.cnet.com as its official website but uses the subdomain download.cnet.com for its download hosting site. The FQDN download.cnet.com uses as the same protocol www.cnet.com but directs visitors to the different website.