C2 or a derivative (C-2, C², etc.) may refer to:

Mathematics and physics

* ''C''₂, one of the common notations for the cyclic group of order 2 * ''C''²

differentiability class In mathematical analysis, the smoothness of a function (mathematics), function is a property measured by the number of Continuous function, continuous Derivative (mathematics), derivatives it has over some domain, called ''differentiability cl ...

* ''c''² the square of the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit ...

(in the mass–energy equivalence formula)

Biology

* C2 domain, a protein structural domain * C2 regulatory sequence for the insulin gene * Apolipoprotein C2, a human apolipoprotein * In human anatomy, C2 may refer to: **

Cervical vertebra 2 In anatomy, the axis (from Latin ''axis'', "axle") or epistropheus is the second cervical vertebra (C2) of the spine, immediately inferior to the atlas, upon which the head rests. The axis' defining feature is its strong odontoid process (bon ...

, the axis, one of the cervical vertebrae of the vertebral column **

Cervical spinal nerve 2 The cervical spinal nerve 2 (C2) is a spinal nerve of the cervical segment.American Medical Association

Chlorophyll c2 Chlorophyll ''c'' is a form of chlorophyll found in certain marine algae, including the photosynthetic Chromista (e.g. diatoms and brown algae) and dinoflagellates. It has a blue-green color and is an accessory pigment, particularly significant i ...

, a form of chlorophyll * Complement component 2 * Procyanidin C2, a plant phenolic compound *

Prodelphinidin C2 Prodelphinidin C2 is a prodelphinidin trimer found in malt Malt is germinated cereal grain that has been dried in a process known as " malting". The grain is made to germinate by soaking in water and is then halted from germinating further ...

, a plant phenolic compound *

Vitamin C2 Choline is an essential nutrient for humans and many other animals. Choline occurs as a cation that forms various salts (X− in the depicted formula is an undefined counteranion). Humans are capable of some ''de novo synthesis'' of choline but re ...

, a name sometimes used for Choline * the ATC code for ''

Antihypertensives Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke and myocardial infarction. Evidence suggests that r ...

'', a subgroup of the Anatomical Therapeutic Chemical Classification System *C₂ fragments, one of the types of products of

catabolism Catabolism () is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions. Catabolism breaks down large molecules (such as polysaccharides, lipids, ...

pathways * Haplogroup C-M217, also known as C2, a

Human Y-chromosome DNA haplogroup In human genetics, a human Y-chromosome DNA haplogroup is a haplogroup defined by mutations in the non- recombining portions of DNA from the male-specific Y chromosome (called Y-DNA). Many people within a haplogroup share similar numbers of sh ...

Chemistry

* C₂, Diatomic carbon, a molecule made of two carbon atoms * C2=,

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene i ...

, a two carbon alkene

Codes or abbreviations

C2 may be a code or abbreviation for: * C² Aquarii, a star * C² Centauri, a star * C2 (Code Geass), an anime character * C2 explosive, a form of plastic explosive * C2 pylon, a type of high voltage pylon * C2 radio class, a class in FM broadcasting in America * C2 (classification), a para-cycling classification * Group C2, the secondary class of Group C sports car racing * BRDC C2 Championship, a short lived sports car racing series which ran from 1988 to 1990 * Nimrod NRA/C2, a 1982 Group C racing car * C2, an international standard paper size defined in

ISO 216 ISO 216 is an international standard for paper sizes, used around the world except in North America and parts of Latin America. The standard defines the "A", "B" and "C" series of paper sizes, including A4, the most commonly available paper size ...

(458×648 mm) * C2, a level in the

Common European Framework of Reference for Languages The Common European Framework of Reference for Languages: Learning, Teaching, Assessment, abbreviated in English as CEFR or CEF or CEFRL, is a guideline used to describe achievements of learners of foreign languages across Europe and, increasing ...

* C2, the

NRS social grade The NRS social grades are a system of demographic classification used in the United Kingdom. They were originally developed by the National Readership Survey (NRS) to classify readers, but are now used by many other organisations for wider appli ...

between C1 and D *

Command and control Command and control (abbr. C2) is a "set of organizational and technical attributes and processes ... hatemploys human, physical, and information resources to solve problems and accomplish missions" to achieve the goals of an organization or en ...

, the exercise of authority by a commanding officer over military forces in the accomplishment of a mission *

Air Luxor Air Luxor was an airline based in Luxor Plaza in Lisbon, Portugal, operating a limited number of scheduled flights out of Portela Airport, Lisbon. The airline's operations were located in Building C1 and Hangar 7 in Delta Park, an area in Lis ...

IATA airline code *

C2 Pictures C2 Pictures was an American independent media-entertainment company, it specialized in film and television production. History The company was established in 1998 by Carolco Pictures co-founders Andrew G. Vajna (who had formed Cinergi Pictur ...

, a film company related to Carolco Pictures * Bill C-2, various legislation of the Parliament of Canada * C2, or C₂ a note-octave in music, aka

Low C C or Do is the first note and semitone of the C major scale, the third note of the A minor scale (the relative minor of C major), and the fourth note (G, A, B, C) of the Guidonian hand, commonly pitched around 261.63 Hz. The actual frequen ...

Computing

* C2, a computer security class, defined in the Trusted Computer System Evaluation Criteria * C2, a bytecode compiler that is part of the

HotSpot Hotspot, Hot Spot or Hot spot may refer to: Places * Hot Spot, Kentucky, a community in the United States Arts, entertainment, and media Fictional entities * Hot Spot (comics), a name for the DC Comics character Isaiah Crockett * Hot Spot (Tra ...

virtual machine implementation *

C2 (protocol) Punter is a protocol for file transfer developed in the 1980s by Steve Punter. There are various types of Punter such as PET Transfer Protocol (''PTP''), ''C1'' and ''C2''. PET Transfer Protocol The PET Transfer Protocol (''PTP''), also known a ...

, a 1985 Commodore file transfer protocol *

C2 error A C2 error, also known as E32 error, is a read error of a Compact Disc. C2 errors can to a degree be recovered by the hardware error detection and correction scheme. A CD drive can have extraction errors when the data on the disc is not readable due ...

, a read error of a compact disc *

C2.com The WikiWikiWeb is the first wiki, or user-editable website. It was launched on 25 March 1995 by programmer Ward Cunningham to accompany the Portland Pattern Repository website discussing software design patterns. The name ''WikiWikiWeb'' orig ...

or WikiWikiWeb, the first user-editable website *

Cryptomeria cipher The Cryptomeria cipher, also called C2, is a proprietary block cipher defined and licensed by the 4C Entity. It is the successor to CSS algorithm (used for DVD-Video) and was designed for the CPRM/CPPM digital rights management scheme which are ...

, a cipher used in digital rights management * Command and control (malware) *

Codec 2 Codec 2 is a low-bitrate speech audio codec (speech coding) that is patent free and open source. Codec 2 compresses speech using sinusoidal coding, a method specialized for human speech. Bit rates of 3200 to 450 bit/s have been successfully cre ...

, speech compression codec.

Transportation and space

C2 class Melbourne tram The C2-class trams are five-section Alstom Citadis 302 trams built in La Rochelle, France that operate on the Trams in Melbourne, Melbourne tram network. They were built for the tram network in Mulhouse tramway, Mulhouse, France, but being surp ...

* Bavarian C II (Ostbahn), an 1862 German steam locomotive * Bavarian C II.1, an 1857 German steam locomotive * Bavarian C II.2, an 1861 German steam locomotive * Chevrolet Corvette (C2), the generation of the Chevrolet Corvette produced between 1962 and 1967 *

Citroën C2 The Citroën C2 is a supermini that was produced by the French manufacturer Citroën, with production starting August 2003. It replaced the Citroën Saxo and was built at the Aulnay plant, on the outskirts of Paris. The Citroën C2 was discontin ...

, a car produced by Citroën in 2004 * Cluster II (spacecraft), an ESA space mission *

GNR Class C2 The Great Northern Railway class C2 locomotives were a class of 4-4-2 tank locomotives built by the Great Northern Railway (GNR) between 1898 and 1907. They were used on local and commuter passenger trains in Yorkshire and North London. They ...

, a British 4-4-2 steam locomotive class * LNER Class C2, classified C1 during GNR ownership *

Kawasaki C2 The Kawasaki C2SS 120 and C2TR 120 Roadrunner were Kawasaki motorcycles made from 1964 to 1969. The C2SS was designed as a street scrambler; a road machine powered by a single cylinder, two stroke, rotary disc valve engine with a displacement ...

, a bike *

London Buses route C2 This is a list of Transport for London (TfL) contracted bus routes in London, England, as well as commercial services that enter the Greater London area (except coaches). Bus services in London are operated by Abellio London, Arriva London, ...

LB&SCR C2 class The London, Brighton and South Coast Railway C2 class was a class of 0-6-0 steam locomotives, intended for heavy freight trains. Fifty-five were built by the Vulcan Foundry between 1893 and 1902 to the design of Robert J. Billinton. Forty-fiv ...

, an 1893 British 0-6-0 steam locomotive * Circumferential Road 2 or C-2, an arterial road of Manila, Philippines * Saf-T-Liner C2, a school bus built by Thomas Built Buses *

Saturn C-2 The Saturn C-2 was the second rocket in the Saturn C series studied from 1959 to 1962. The design was for a four-stage launch vehicle that could launch 21,500 kg (47,300 lb) to low Earth orbit and send 6,800 kg (14,900 lb) to t ...

, a 1960 conceptual American launch vehicle * Type C2 ship, a type of all-purpose cargo ship *

C2 (yacht) ''C2'' is a super-yacht built in 2008 at the shipyard Abeking & Rasmussen. The interior and exterior design of ''C2'' was done by Reymond Langton Design Ltd. The yacht has three sister-ships, ''Ameryllis'', ''Eminence'' and ''Titan''. Design ...

, a luxury motor yacht *

Central Circular Route (Shuto Expressway) The , signed as Route C2, is one of the routes of the Shuto Expressway system serving the central part of the Greater Tokyo Area. The route is a circumferential highway running through the outer wards of Tokyo. The route is the middle of fou ...

in Tokyo, Japan *

Mei-Nikan Expressway The , or , is a partially completed tolled expressway in Japan. It is owned and operated by the Central Nippon Expressway Company. Upon completion, the expressway will form a second ring road around Nagoya in conjunction with the Isewangan Expre ...

, route C2 in Nagoya, Japan

Military and aviation

C2A1 The L1A1 Self-Loading Rifle, officially "Rifle, 7.62mm, L1A1", also known just as the SLR (Self-Loading Rifle), by the Canadian Army designation C1A1 (C1) or in the US as the "inch pattern" FAL,Especially on the American surplus market. is a Br ...

, Squad Automatic Weapon variant of the FN FAL formerly in Canadian Service * C-2 Greyhound, the Grumman cargo aircraft of the United States Navy * ACAZ C.2, a Belgian prototype fighter aircraft of the 1920s *

AEG C.II The AEG C.II was a German two-seat biplane reconnaissance aircraft produced in small numbers from October 1915. It was a slightly smaller version of the C.I with better performance, redesigned cockpit for both pilot and observer/bombardier, new r ...

, a German World War II armed reconnaissance aircraft *

AGO C.II The AGO C.II was a German reconnaissance biplane of World War I. It was essentially a slightly redesigned version of the manufacturer's C.I design with a more powerful engine and 3-bay wings. Two examples were equipped with floats (designation ...

, a German reconnaissance biplane of World War I * Cierva C.2, a 1921 Spanish experimental autogyro *

DFW C.II __NOTOC__ The DFW C.I was a German reconnaissance aircraft produced during World War I. Derived from the company's B.I design of 1914, the C.I kept the same basic fuselage design, but dispensed with the B.I's distinctive crescent-shaped wings, r ...

, a World War I German reconnaissance aircraft * Fokker C-2, the American military version of the Fokker F.VII aircraft * , a British C class submarine of the Royal Navy * Kawasaki C-2, a military transport aircraft *

LFG Roland C.II The LFG Roland C.II, usually known as the ''Walfisch'' (Whale), was an advanced German reconnaissance aircraft of World War I. It was manufactured by Luft-Fahrzeug-Gesellschaft G.m.b.H. Characteristics The C.II had much lower drag than comparab ...

, a 1915 advanced German reconnaissance aircraft *

LVG C.II The LVG C.II was a 1910s German two-seat reconnaissance biplane designed at the Luft-Verkehrs-Gesellschaft for the '' Luftstreitkräfte''. Development The C.II was developed from the LVG B.I, with the pilot and observer positions reversed, ad ...

, a 1910s German two-seat reconnaissance biplane * , a C-class submarine of the United States Navy * , a protected cruiser of the United States Navy * A military term for

C-2 (poison) The poison laboratory of the Soviet secret services, alternatively known as Laboratory 1, Laboratory 12, and Kamera (which means "The Cell" in Russian language, Russian), was a covert Research and development , research-and-development facili ...

, developed in the ''Poison laboratory of the Soviet secret services''

Other

* C2,

UEFA Cup Winners' Cup The UEFA Cup Winners' Cup was a European football club competition contested annually by the winners of domestic cup competitions. The cup was, chronologically, the second seasonal inter-European club competition organised by UEFA. The tournam ...

in football, later merged with UEFA Cup (now

UEFA Europa League The UEFA Europa League (abbreviated as UEL, or sometimes, UEFA EL), formerly the UEFA Cup, is an annual football club competition organised since 1971 by the Union of European Football Associations (UEFA) for eligible European football clubs. It ...

) *

, a film studio * C-2 visa, a nonimmigrant visa which allows individuals to travel to and from the headquarters of the United Nations *

Coca-Cola C2 Coca-Cola C2 (also referred to as Coke C2, C2 Cola, or simply C2) was a cola-flavored beverage introduced by The Coca-Cola Company first in Japan, then later on June 7, 2004 in the United States (and shortly thereafter, Canada), in response to t ...

, a soft drink launched by The Coca-Cola Company in 2004