A domain at the top of the naming hierarchy of the Domain Name System. In a domain name, the TLD appears after the second-level domain. For example, in the domain name icann.org, the characters org identify the TLD.
The administrators of a TLD control which second-level domains are recognized within the TLD. TLDs fall into two classes: generic top-level domains (e.g., .com, .net, .edu) and country code top-level domains (e.g., .jp, .de, .in).