What is TLD?
Also known as: Top-Level Domain
A TLD (Top-Level Domain) is the last segment of a domain name, such as .com or .uk, directly delegated from the DNS root zone.
A Top-Level Domain (TLD) is the highest hierarchical level in the Domain Name System (DNS), representing the rightmost component of a fully qualified domain name (FQDN). For example, in "example.com", "com" is the TLD. TLDs are managed by the Internet Assigned Numbers Authority (IANA) and delegated to registry operators, who maintain the authoritative database of second-level domains under each TLD.
The DNS root zone contains pointers to all TLD nameservers. When a recursive resolver processes a query for "www.example.com", it first contacts a root nameserver to find the nameserver for ".com", then queries that nameserver to locate the authoritative nameserver for "example.com". This delegation chain relies on TLDs as the first branching point below the root.
TLDs fall into several categories: generic TLDs (gTLDs) like .com, .org, .net; country-code TLDs (ccTLDs) like .uk, .de, .jp; sponsored TLDs (sTLDs) like .aero, .museum; and newer generic ones from ICANN's expansion program, such as .dev, .app. The root zone is managed by ICANN under a contract with the U.S. Department of Commerce, with daily updates coordinated via the Root Zone Maintainer (currently ICANN subsidiary PTI).
Key facts
- TLD is the highest level of the DNS hierarchy, directly under the root (.).
- ICANN delegates TLD management to registry operators via contract.
- There were 1,500+ TLDs as of 2024, including both gTLDs and ccTLDs.
- ccTLDs are two-letter codes per ISO 3166-1, allocated to countries or territories.
- The DNS root zone is served by 13 logical root nameservers (a.root-servers.net through m.root-servers.net).
How it works in practice
Related terms
References
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