What is a TLD?¶

Also known as a ‘Domain Name Extension’, a Top Level Domain (TLD) is the last bit of a domain that goes on the end of the address, after the dot. For example, .com, .co.uk.

The basic purpose of the TLD is to tell you something about the domain; for example, historically the top-level domains were grouped by countries, categories and multi-organisations.

For example, a .edu TLD would tell you that the organisation was part of the education system, .com would signify commercial, or a .co.uk would tell you it was from the UK.

The responsibility of the management of most TLDs is given by the jurisdiction of the Internet Corporation for Assigned Names and Numbers (ICANN).

ICANN identifies the following categories of TLDs:

• Country-code top-level domains (ccTLD) -- Each ccTLD identifies a particular country and is two letters long. The ccTLD for the United States, for example, is `.us`
• Sponsored top-level domains (sTLD): These are overseen by private organisations.
• Generic top-level domains (gTLD) -- These are the most common and familiar TLDs. Examples include `.com` for commercial and `.edu` for educational. Most gTLDs are open for registration by anyone, but there is also a subgroup that is more strictly controlled.
• Infrastructure top-level domain -- There is only one TLD in this group, ARPA (Address and Routing Parameter Area). The Internet Assigned Numbers Authority (IANA) manages this TLD for the IETF.

Previously the registration of TLDs was restricted but as of early 2014 anyone can register an unused TLD for their own personal use. This means that anything from .academy to .zone is available for the quickest bidder.