What is FQDN (fully qualified domain name)?

A fully qualified domain name (FQDN), is a domain name that indicates its definite location in the tree hierarchy of the Domain Name System (DNS). Fully Qualified Domain Names (FQDN) are complete addresses of sites, computers and different elements that can be accessed on the Internet. An FQDN comprises three labels, incorporating the hostname, second-level domain name and top-level domain name (TLD), each isolated by a period.