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

Chemistry and physics

* Sodium, symbol Na, a chemical element * Avogadro constant (''N''_A) *

Nucleophilic addition In organic chemistry, a nucleophilic addition reaction is an addition reaction where a chemical compound with an electrophilic double or triple bond reacts with a nucleophile, such that the double or triple bond is broken. Nucleophilic additions di ...

, 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, NA has the proper ...

, a number that characterizes a range of angles in an optical system * nA, the symbol for

nanoampere The ampere (, ; symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. is the unit of electric current in the International System of Units (SI). One ampere is equal to ele ...

Naturally aspirated engine Naturally may refer to: ;Albums * ''Naturally!'', an album by Nat Adderley * ''Naturally'' (Houston Person album) * ''Naturally'' (J. J. Cale album) * ''Naturally'' (John Pizzarelli album) * ''Naturally'' (Sharon Jones album) * ''Naturally'' ...

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 Nucleic acid analogues are compounds which are Analog (chemistry), analogous (structurally similar) to naturally occurring RNA and DNA, used in medicine and in molecular biology research. Nucleic acids are chains of nucleotides, which are compos ...

, compounds analogous to naturally occurring RNA and DNA

Places

Current

* Namibia (ISO country code) * Naples (car number plate code: NA), Italy *

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, a continent * North Africa, a subcontinent

Historical

Netherlands Antilles nl, In vrijheid verenigd"Unified by freedom" , national_anthem = , common_languages = Dutch English Papiamento , demonym = Netherlands Antillean , capital = Willemstad , year_start = 1954 , year_end = 2010 , date_start = 15 December , ...

(former international vehicle registration code: NA) *

Na (Chinese state) The State of Na (, also written as 冉) was a minor state in Ancient China. History During the Zhou Dynasty in the 11th century BCE, the Duke of Zhou received orders from King Cheng of Zhou to announce an edict concerning descendants of the roya ...

, 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

Transport

* NA, the tailcode of VFA-94 * Nepal Airlines, the national flag carrier airline of Nepal * North American Airlines (IATA code: NA) *

* Mazda MX-5 (NA), 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 National bank#United States, federally chartered banks in the United States * Mosuo or Na, an ethnic group in China near Tibet * Na people, an ethnic group in India