A top-level domain (TLD) is one of the domains at the highest level in the hierarchical Domain Name System of the Internet.[1]

The top-level domain names are installed in the root zoneof the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last label of a fully qualified domain name. For example, in the domain namewww.example.com, the top-level domain is .com (the “dot” and the word that follows it).