NA, N.A., Na, nA or n/a may refer to:

Chemistry and physics

Sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

, symbol Na, a chemical element * Avogadro constant (''N''_A) * Nucleophilic addition, a type of reaction in organic chemistry *

Numerical aperture In optics, the numerical aperture (NA) of an optical system is a dimensionless number that characterizes the range of angles over which the system can accept or emit light. By incorporating index of refraction in its definition, has the property ...

, 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) ''Mesua ferrea'', the Ceylon ironwood, or cobra saffron, is a species in the family (biology), family Calophyllaceae native to the Indomalayan realm. This slow-growing tree is named after the heaviness and hardness of its timber. It is widely c ...

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 Namibia, officially the Republic of Namibia, is a country on the west coast of Southern Africa. Its borders include the Atlantic Ocean to the west, Angola and Zambia to the north, Botswana to the east and South Africa to the south; in the no ...

(ISO country code) *

Naples Naples ( ; ; ) is the Regions of Italy, regional capital of Campania and the third-largest city of Italy, after Rome and Milan, with a population of 908,082 within the city's administrative limits as of 2025, while its Metropolitan City of N ...

(car number plate code: NA), Italy *

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, a continent *

North Africa North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...

, a subcontinent

Historical

Netherlands Antilles The Netherlands Antilles (, ; ), also known as the Dutch Antilles, was a constituent Caribbean country of the Kingdom of the Netherlands consisting of the islands of Saba (island), Saba, Sint Eustatius, and Sint Maarten in the Lesser 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 was a stateIn Japanese, the character 国/國, read as ''koku'' (in on'yomi) or ''kuni'' (in kun'yomi), can be translated as "country" or "province" which was located in and around modern-day Fukuoka City, on the Japanese island of Kyūsh ...

, 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 The ''Virgin New Adventures'' (NA series, or NAs) are a series of novels from Virgin Publishing based on the British Science fiction on television, science-fiction television series ''Doctor Who''. They continued the story of the Doctor from th ...

'', a series of ''Doctor Who'' novels * ''Na'' (EP) by Nayeon, 2024

Transport

* NA, the tailcode of

VFA-94 Strike Fighter Squadron 94 (VFA-94), also known as the Mighty Shrikes, is a United States Navy fighter squadron stationed at Naval Air Station Lemoore. It is an operational fleet squadron currently flying the Boeing F/A-18E/F Super Hornet, F/A-1 ...

Nepal Airlines Nepal Airlines Corporation (), formerly known as Royal Nepal Airlines (), is the flag carrier of Nepal. Founded in 1958, it is the oldest airline of the country. Out of its main base at Tribhuvan International Airport, Kathmandu, the airline ope ...

, the national flag carrier airline of Nepal *

North American Airlines North American Airlines, Inc., was an American airline with its headquarters at the HLH Building in Peachtree City, Georgia in Greater Atlanta, United States. Prior to May 2008, it operated scheduled international services from the U.S. to Afri ...

(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

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 National archives are the archives of a country. The concept evolved in various nations at the dawn of modernity based on the impact of nationalism upon bureaucratic processes of paperwork retention. Conceptual development From the Middle Ages i ...

, the archives of a country