High Quality Content by WIKIPEDIA articles! A hostname is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication such as the World Wide Web, e-mail or Usenet. Hostnames may be simple names consisting of a single word or phrase, or they may have appended the name of a Domain Name System (DNS) domain, separated from the host specific label by a period (dot). In the latter form, a hostname is also called a domain name. If the domain name is completely specified including a top-level domain of the Internet, the hostname is said to be a fully qualified domain name (FQDN).