A top-level domain (TLD) is one of the domains at the highest level in the hierarchical Domain Name System of the Internet after the root domain. The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last non empty label of a fully qualified domain name. For example, in the domain name www.example.com, the top-level domain is .com. Responsibility for management of most top-level domains is delegated to specific organizations by the ICANN, an Internet multi-stakeholder community, which operates the Internet Assigned Numbers Authority (IANA), and is in charge of maintaining the DNS root zone.
In the Internet, a domain name is a string that identifies a realm of administrative autonomy, authority or control. Domain names are often used to identify services provided through the Internet, such as websites, email services and more. Domain names are used in various networking contexts and for application-specific naming and addressing purposes. In general, a domain name identifies a network domain or an Internet Protocol (IP) resource, such as a personal computer used to access the Internet, or a server computer.
An internationalized domain name (IDN) is an Internet domain name that contains at least one label displayed in software applications, in whole or in part, in non-Latin script or alphabet or in the Latin alphabet-based characters with diacritics or ligatures. These writing systems are encoded by computers in multibyte Unicode. Internationalized domain names are stored in the Domain Name System (DNS) as ASCII strings using Punycode transcription.
.us is the Internet country code top-level domain (ccTLD) for the United States. It was established in early 1985. Registrants of .us domains must be U.S. citizens, residents, or organizations – or foreign entities with a presence in the United States or any territory of the United States. Most registrants in the U.S. have registered for .com, .net, .org and other gTLDs, instead of .us, which has primarily been used by state and local governments, even though private entities may also register .us domains. The domain is managed by Registry Services, LLC, a domain name registry, on behalf of the United States Department of Commerce.
.uk is the Internet country code top-level domain (ccTLD) for the United Kingdom. It was first registered in July 1985, seven months after the original generic top-level domains such as .com and the first country code after .us.
.nu is the Internet country code top-level domain (ccTLD) assigned to the island state of Niue. It was one of the first ccTLDs to be marketed to the Internet at large as an alternative to the gTLDs .com, .net, and .org. Playing on the phonetic similarity between nu and new in English, and the fact that nu means "now" in several northern European languages, it was promoted as a new TLD with an abundance of good domain names available. The .nu domain is now controlled by the Internet Foundation in Sweden amid opposition from the government of Niue.
A country code top-level domain (ccTLD) is an Internet top-level domain generally used or reserved for a country, sovereign state, or dependent territory identified with a country code. All ASCII ccTLD identifiers are two letters long, and all two-letter top-level domains are ccTLDs.
.ae is the country code top-level domain (ccTLD) in the Domain Name System of the Internet for the United Arab Emirates. It is administered by .aeDA which is part of the Telecommunications and Digital Government Regulatory Authority of UAE (TDRA).
.su is an Internet country code top-level domain (ccTLD) that was designated for the Union of Soviet Socialist Republics (USSR) on 19 September 1990. Even though the Soviet Union itself was dissolved 15 months later, the .su top-level domain remains in use to the present day. It is administered by the Russian Institute for Public Networks.
The Canadian Internet Registration Authority (CIRA) is the organization that manages the .ca country code top-level domain (ccTLD) for Canada. Its offices are located at 979 Bank Street in Ottawa, Ontario, Canada. CIRA sets the policies and agendas that support Canada's internet community and Canada's involvement in international internet governance. It is a member-driven organization with membership open to all that hold a .ca domain. As of March 2023, there were more than 3.3 million active .ca domains.
.fr is the Internet country code top-level domain (ccTLD) in the Domain Name System of the Internet for France. It is administered by AFNIC. The domain includes all individuals and organizations registered at the Association française pour le nommage Internet en coopération (AFNIC).
.er is the country code top-level domain (ccTLD) for Eritrea.
A sponsored top-level domain (sTLD) is one of the categories of top-level domains (TLDs) maintained by the Internet Assigned Numbers Authority (IANA) for use in the Domain Name System of the Internet, alongside country-code top-level domains (ccTLD) and generic top-level domains (gTLD).
.vc is the Internet country code top-level domain (ccTLD) for Saint Vincent and the Grenadines.
.vg is the Internet country code top-level domain (ccTLD) for the British Virgin Islands. Because it allows registration at the second level, and does not require the registrant to be associated with the British Virgin Islands, it has also been used by piracy related websites such as The Pirate Bay, and video gaming related blogs and websites.
.uz is the Internet country code top-level domain (ccTLD) for Uzbekistan. Registry services were formerly operated by Euracom GmBH, but were later redelegated to UZINFOCOM. Registrations are taken directly at the second level, but the former registry also advertised the availability of registrations at the third level beneath co.uz and com.uz, and some domain names under other second-level names such as org.uz also exist.
.so is the internet country code top-level domain (ccTLD) for Somalia. After a long absence, the .so domain was officially relaunched on November 1, 2010, by .SO Registry, which is regulated by the nation's Ministry of Posts and Telecommunications. It was launched through various accredited registrars around the world.
.ma is the Internet country code top-level domain (ccTLD) for Morocco. A local registrar with a local Moroccan company as administrative contact is needed to register a .ma or .co.ma domain name. Further restrictions are imposed on the registering of other second-level domains.
.berlin (dotBERLIN) is an approved top level domain (TLD) for the Internet. It is a community-based sponsored top-level domain for Berliners. According to the dotBERLIN Organization, .berlin will allow all Berliners to register their domains under .berlin
