Businesses and organizations

* Air Tahiti Nui (IATA airline designation "TN" since 1998), a French Polynesian airline * Texas and Northern Railway, an American railway (reporting mark "TN") * Todo Noticias, an Argentine cable news network * Trans Australia Airlines (IATA airline designation "TN" until 1994), a defunct Australian airline * Transports en commun de Neuchâtel et environs, a public transport operator in Neuchâtel, Switzerland

Places

* Tamil Nadu, a state in southern India (ISO abbreviation "IN-TN") * Tennessee, US (postal abbreviation "TN") * Tonbridge, a region in England (postcode "TN") * Tunisia (ISO 3166-1 country code "TN") * Trentino, a province in Italy (ISO abbreviation "IT-TN") ;Other * North Tipperary, Ireland (former code "TN")

Science and technology

* .tn, the country code top level domain (ccTLD) for Tunisia * TN-C#TN networks, TN network, a type of earthing system for protection in electricity network * Neel Temperature, the temperature at which an antiferromagnetic material becomes paramagnetic (represented as T_N) * ''Tetraodon'', a genus of pufferfish * Trigeminal neuralgia, a neuropathic disorder * Transposon (when immediately followed by a number), a DNA sequence that can change positions * Twisted nematic field effect, the technology that made LCD displays practical * Thoron, symbol Tn, a sometimes used name for the nuclide radon-220

Other uses

* TN status ("Treaty national", or "Trade NAFTA"), an immigration status of a Canadian or Mexican citizen working in the USA under the NAFTA agreement * Telephone number, in the telecommunications industry * Tom Next (or Tomorrow Next), a financial trade which starts tomorrow and settlement (finance), settles in the next trading day * Trillion ("TN" or "tn"), a number equal to 10¹² (short scale) or 10¹⁸ (long scale) * Tswana language (ISO 639-1 language code) * Translators Note ("TN" or "t/n") * ''Turbonave'', an Italian ship prefix, indicating that the ship was propelled by a gas turbine, turbine engine. {{disambiguation