In the Domain Name System (DNS) hierarchy, a second-level domain (SLD or 2LD) is a domain that is directly below a top-level domain (TLD). For example, in , is the second-level domain of the TLD. Second-level domains commonly refer to the organization that registered the domain name with a domain name registrar. Some domain name registries introduce a second-level hierarchy to a TLD that indicates the type of entity intended to register an SLD under it. For example, in the .uk namespace a college or other academic institution would register under the ccSLD, while companies would register under . Strictly speaking, domains like .ac.uk and .co.uk are second level domain themselves, since they are right below a TLD. A list of the official TLDs can be found at icann.org and iana.org. An ordinal-free term to denote domains under which people can register their own domain name is public suffix domain (PSD). Country-code second-level domains Algeria Australia Austria In Austria there are two second-level domains available for the public: .co.at intended for commercial enterprises .or.at intended for organizations. The second-level domain .priv.at is restricted to Austrian citizens only, while .ac.at and .gv.at are reserved for educational institutions and governmental bodies respectively. Brazil France In France, there are various second-level domains available for certain sectors, including .avocat.fr for attorneys, .aeroport.fr for airports and .veterinaire.fr for vets. Hungary New Zealand Pakistan India Israel Japan Russia South Africa South Korea Spain Sri Lanka Thailand Trinidad and Tobago co.tt com.tt org.tt net.tt travel.tt museum.tt aero.tt tel.tt name.tt charity.tt mil.tt edu.tt gov.tt Turkey In Turkey, domain registrations, including the registration of second-level domains is administrated by nic.tr. There 17 active second-level domains under the .tr TLD. The registration of domains is restricted to Turkish individuals and businesses, or foreign companies with a business activity in Turkey. Second-level domains include .com.tr for commercial ventures, .edu.tr for academic institutions and .name.tr for personal use. Ukraine Ukraine second-level domains include: .gov.ua – available for government agencies. .com.ua – for commercial use. .in.ua – for commercial use. .org.ua – intended for non-profit organizations. .net.ua – intended for Internet providers. .edu.ua – for academic institutions. There are also numerous geographic names. United Kingdom United States A two-letter second-level domain is formally reserved for each U.S. state, federal territory, and the District of Columbia. Zambia Historic second-level domains There are several second-level domains which are no longer available. Australia Second-level domains under