NA, N.A., Na, nA or n/a may refer to:
Chemistry and physics Sodium, symbol Na, a chemical element Avogadro constant (NA) Nucleophilic addition, a type of reaction in organic chemistry Numerical aperture, a number that characterizes a range of angles in an optical system nA, the symbol for nanoampere Naturally aspirated engine
Biology and medicine Na (tree) or Mesua ferrea, a species of tree native to Sri Lanka Neuroacanthocytosis, a neurological condition Nomina Anatomica, a former international standard for human anatomical nomenclature Noradrenaline, a hormone Nucleic acid analogue, compounds analogous to naturally occurring RNA and DNA
Places Current Namibia (ISO country code) Naples (car number plate code: NA), Italy North America, a continent North Africa, a subcontinent
Historical Netherlands Antilles (former international vehicle registration code: NA) Na (Chinese state), a small state of the Chinese Zhou dynasty from the 11th to 8th centuries BC Nakoku, or Na, a state in Kyūshū, Japan from the 1st to early 3rd centuries AD
Names and titles Na (羅), a Korean surname related to the Chinese surname Luo Na, a particle used in Thai noble names National Academician, a member of the National Academy of Design
Art and entertainment Na (drum), a drum played by Tibetan shamans Nahal, Shine's pet Bengal tiger on the Nick Jr. TV show Shimmer and Shine New adult fiction, fiction marketed to people 18–30 years old Virgin New Adventures, a series of Doctor Who novels Na (EP) by Nayeon, 2024 N/a (EP) by Izna, 2024 "N/A" (Bring Me the Horizon song), 2024
Transport NA, the tailcode of VFA-94 Nepal Airlines, the national flag carrier airline of Nepal North American Airlines (1990–2014, IATA code: NA) National Airlines (1934–1980) (IATA code: NA) Naturally aspirated engine NA MX-5 Miata, the first generation of the Mazda Miata
Language Na (cuneiform), a cuneiform sign Na (Javanese) (ꦤ), a letter in the Javanese script Na (kana), a Japanese kana Na dialect, a Sino-Tibetan variety of India Na language (Narua), a Sino-Tibetan language of Yunnan, China Nauruan language (ISO code: na)
Organizations Narcotics Anonymous (NA), a twelve-step program that focuses on recovery from drug addiction National Alliance (Latvia), a Latvian political party National Alliance (Netherlands), a former Dutch political party National Association (disambiguation) National Association of Professional Base Ball Players, the first professional baseball league Nepali Army, the land military force of Nepal Neurotics Anonymous (N/A), a program for recovery from mental and emotional illness New Alternative, a parliamentary group in Finland
Other uses .na, the top-level domain for Namibia N/A, meaning not applicable, not available, or no answer N.A., the official designation of federally chartered banks in the United States Mosuo or Na, an ethnic group in China near Tibet Na people, an ethnic group in India National Archives, the archives of a country
See also Nå (disambiguation) Na Na (disambiguation) Na Na Na (disambiguation) NAA (disambiguation) Nah (disambiguation) Nas (disambiguation)