Top Level Domain
A top level domain is the right most suffix of a domain name. For example, gandalf.example.com consist of three labels, where .com is the TLD, example is considered the domain, and gandalf the host name or in some cases a sub-domain. There are several top level domains such as .aero, .biz, .com, .info, .musuem, .net, .org, which are commonly-referred to as global TLDs (gTLD). There are also TLDs by county code such as .ca, .fr, .jp, .us, .uk to name a few, which are referred to as a country code TLDs (ccTLD). IANA maintains the current database of TLDs.