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 In abstract algebra, a cyclic group or monogenous group is a Group (mathematics), group, denoted C_n (also frequently \Z_n or Z_n, not to be confused with the commutative ring of P-adic number, -adic numbers), that is Generating set of a group, ge ...

of order 2 * ''C''²

differentiability class In mathematical analysis, the smoothness of a function is a property measured by the number of continuous derivatives (''differentiability class)'' it has over its domain. A function of class C^k is a function of smoothness at least ; t ...

* ''C''² or

\Complex^2

, the

complex coordinate plane In mathematics, the ''n''-dimensional complex coordinate space (or complex ''n''-space) is the set of all ordered ''n''-tuples of complex numbers, also known as ''complex vectors''. The space is denoted \Complex^n, and is the ''n''-fold Cartesia ...

* ''c''² the square of the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant exactly equal to ). It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time i ...

(in the mass–energy equivalence formula)

Biology

C2 domain A C2 domain is a protein structural domain involved in targeting proteins to cell membranes. The typical version (PKC-C2) has a beta-sandwich composed of 8 β-strands that co-ordinates two or three calcium ions, which bind in a cavity formed by th ...

, a protein structural domain *

C2 regulatory sequence Transcription of insulin is regulated by the binding of various transcription factors to the ~400 base pairs before the insulin transcription start site, called the "insulin regulatory sequence". This sequence is made up of several distinct regions ...

for the insulin gene *

Apolipoprotein C2 Apolipoprotein C-II (Apo-CII, or Apoc-II), or apolipoprotein C2 is a protein that in humans is encoded by the gene. The protein encoded by this gene is secreted in plasma, where it is a component of very low density lipoproteins and chylomicr ...

, a human apolipoprotein * In human anatomy, C2 may refer to: **

Cervical vertebra 2 In anatomy, the axis (from Latin ''axis'', "axle") is the second cervical vertebra (C2) of the spine, immediately inferior to the atlas, upon which the head rests. The spinal cord passes through the axis. The defining feature of the axis is its ...

, 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'' refers to forms of chlorophyll found in certain marine algae, including the photosynthetic Chromista (e.g. diatoms and brown algae) and dinoflagellates. These pigments are characterized by their unusual chemical structure, with a ...

, a form of chlorophyll *

Complement component 2 Complement C2 is a protein that in humans is encoded by the ''C2'' gene. The protein encoded by this gene is part of the classical pathway of the complement system, acting as a multi-domain serine protease. Deficiency of C2 has been associated wi ...

Procyanidin C2 Procyanidin C2 is a B type proanthocyanidin trimer (chemistry), trimer, a type of condensed tannin. Natural occurrences Procyanidin C2 is found in grape seeds (''Vitis vinifera'') and wine, in barley (''Hordeum vulgare''), malt and beer, in ''Be ...

, a plant phenolic compound *

Prodelphinidin C2 Prodelphinidin C2 is a prodelphinidin trimer found in malt Malt is any cereal grain that has been made to germinate by soaking in water and then stopped from germinating further by drying with hot air, a process known as "malting". Malted gr ...

, a plant phenolic compound *

Vitamin C2 (disambiguation) Vitamin C2 or Vitamin C is not a widely recognized term in modern scientific classification. However, it has been historically or erroneously used to refer to various substances, including: * A proprietary trademarked name for a combination of calc ...

* 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, heart failure, kidney failure and myocardial infa ...

'', 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, lipid ...

pathways *

Haplogroup C-M217 Haplogroup C-M217, also known as C2 (and previously as C3), is a Y-chromosome DNA haplogroup. It is the most frequently occurring branch of the wider Haplogroup C (M130). It is found mostly in Central Asia, Eastern Siberia and significant freq ...

, also known as C2, a

Human Y-chromosome DNA haplogroup In human genetics, a human Y-chromosome DNA haplogroup is a haplogroup defined by specific mutations in the non-Genetic recombination, recombining portions of DNA on the male-specific Y chromosome (Y-DNA). Individuals within a haplogroup share ...

Chemistry

* C₂,

Diatomic carbon Diatomic carbon (systematically named dicarbon and 1λ2,2λ2-ethene), is a green, gaseous inorganic chemical with the chemical formula C=C (also written 2or C2). It is kinetically unstable at ambient temperature and pressure, being removed throug ...

, 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 bond, carbon–carbon doub ...

, 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) is the pseudonym of a fictional character in the '' Code Geass: Lelouch of the Rebellion'' franchise by Sunrise. With her real name kept from the audience, she first appeared in the 2006 initial anime season, and afterwards has appeared in many ...

, an anime character *

C2 explosive The Composition C family is a family of related US-specified plastic explosives consisting primarily of RDX. All can be moulded by hand for use in demolition work and packed by hand into shaped-charge devices. Variants have different proportions a ...

, a form of plastic explosive *

C2 pylon A transmission tower (also electricity pylon, hydro tower, or pylon) is a tall structure, usually a lattice tower made of steel that is used to support an overhead power line. In electrical grids, transmission towers carry high-voltage transmissi ...

, a type of high voltage pylon *

C2 radio class This is a list of broadcast station classes applicable in much of North America under international agreements between the United States, Canada and Mexico. Effective radiated power (ERP) and height above average terrain (HAAT) are listed unless ot ...

, a class in FM broadcasting in America *

C2 (classification) In Paralympic sports, C2 is a para-cycling classification. The UCI recommends this be coded as MC2 or WC2. Definition PBS defined this classification as "Riders with upper or lower limb impairments and moderate to severe neurological ." ''The T ...

, a para-cycling classification *

Group C2 Group C was a category of sports car racing introduced by the FIA in 1982 and continuing until 1993, with ''Group A'' for touring cars and ''Group B'' for GTs. It was designed to replace both Group 5 special production cars (closed top touri ...

, the secondary class of Group C sports car racing *

BRDC C2 Championship The BRDC C2 Championship (sometimes referred to as the British C2 Championship) was a short lived sports car racing series which ran from 1988 to 1990. The series was for Group C cars which fit into the smaller, less powerful, and cheaper C2 categor ...

, a short lived sports car racing series which ran from 1988 to 1990 *

Nimrod NRA/C2 The Nimrod NRA/C2 was the only Group C racing car ever built by Nimrod Racing Automobiles in partnership with Aston Martin. It ran initially in 1982 in the World Endurance Championship before also joining the IMSA GT Championship. The final NR ...

, 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, which includes the A4, the most commonly availabl ...

(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, CEF, or CEFRL, is a guideline used to describe achievements of learners of foreign languages across Europe and, increasingl ...

* 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 have since been used by many other organisations for w ...

between C1 and D * C2s, substances listed in Schedule II of the Controlled Substances Act in the United States * Command and control, 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 business, independent Media company, media-entertainment company that specialized in Film production, film and television production. History The company was established in 1998 by Carolco Pictures co-fou ...

, a film company related to Carolco Pictures *

Bill C-2 Bill C-2 refers to various legislation introduced into the House of Commons of Canada. Because Bill C-1 is a ''pro forma'' bill asserting the independence of Parliament, Bill C-2 is the first substantive bill introduced into each session of the Ho ...

, 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 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 frequency has depen ...

Computing

* C2, a computer security class, defined in the

Trusted Computer System Evaluation Criteria Trusted Computer System Evaluation Criteria (TCSEC) is a United States Government Department of Defense (DoD) standard that sets basic requirements for assessing the effectiveness of computer security controls built into a computer system. The TC ...

* 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 (Tr ...

virtual machine implementation * C2 (protocol), a 1985 Commodore file transfer protocol *

C2 error A C2 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 to scratches or smudges. ...

, a read error of a compact disc * C2.com 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 ar ...

, a cipher used in digital rights management *

Command and control (malware) A botnet is a group of Internet-connected devices, each of which runs one or more bots. Botnets can be used to perform distributed denial-of-service (DDoS) attacks, steal data, send spam, and allow the attacker to access the device and its conne ...

* Codec 2, speech compression codec.

Transportation and space

* C2 class Melbourne tram * Bavarian C II (Ostbahn), an 1862 German steam locomotive * Bavarian C II.1, an 1857 German steam locomotive *

Bavarian C II.2 The Bavarian C II was a class of early German steam locomotives operated by the Royal Bavarian State Railways (''Königlich Bayerische Staatsbahn''). Articulated variant (''Stütztender'') The first C IIs were built experimentally as articulat ...

, an 1861 German steam locomotive *

Chevrolet Corvette (C2) The Chevrolet Corvette (C2) is the Chevrolet Corvette#Second generation-C2 (1963–1967), second-generation Chevrolet Corvette, Corvette sports car, produced by the Chevrolet division of General Motors (GM) for the 1963 through 1967 model years. ...

, the generation of the Chevrolet Corvette produced between 1962 and 1967 *

Citroën C2 The Citroën C2 is a supermini car, supermini that was produced by the French manufacturer Citroën, with production starting August 2003. It replaced the Citroën Saxo and was built at the PSA Aulnay-sous-Bois Plant, Aulnay plant, on the outskir ...

, a car produced by Citroën in 2004 *

Cluster II (spacecraft) Cluster II was a space mission of the European Space Agency, with NASA participation, to study the Earth's magnetosphere over the course of nearly two solar cycles. The mission was composed of four identical spacecraft flying in a Tetrahedron, t ...

, an ESA space mission *

Ford C2 platform Ford commonly refers to: * Ford Motor Company, an automobile manufacturer founded by Henry Ford * Ford (crossing), a shallow crossing on a river Ford may also refer to: Ford Motor Company * Henry Ford, founder of the Ford Motor Company * Ford F ...

, an automobile platform produced by Ford since 2018 * GNR Class C2, a British 4-4-2 steam locomotive class * LNER Class C2, classified C1 during GNR ownership * Kawasaki C2, 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 Arriva London, Go-Ahead London ( ...

* LB&SCR C2 class, an 1893 British 0-6-0 steam locomotive *

Circumferential Road 2 Circumferential Road 2 (C-2), informally known as the C-2 Road, is a network of roads and bridges which comprise the second beltway of Metro Manila in the Philippines. Spanning some , it connects the districts of Tondo, Manila, Tondo, Santa Cruz ...

or C-2, an arterial road of Manila, Philippines *

Saf-T-Liner C2 The Thomas Saf-T-Liner C2 (often shortened to Thomas C2) is a bus manufactured by Thomas Built Buses since 2004. The first cowled-chassis bus designed by Thomas following its acquisition by Freightliner, the C2 debuted the first all-new bod ...

, a school bus built by Thomas Built Buses * Saturn C-2, a 1960 conceptual American launch vehicle *

Type C2 ship Type C2 ships were designed by the United States Maritime Commission (MARCOM) in 1937–38. They were all-purpose cargo ships with five holds, and U.S. shipyards built 328 of them from 1939 to 1945. Compared to ships built before 1939, the C2s we ...

, a type of all-purpose cargo ship *

C2 (yacht) ''HBC'', formerly known as ''C2'' and then ''B2'', is a superyacht built in 2008 at the shipyard Abeking & Rasmussen. The interior and exterior design of ''HBC'' was done by Reymond Langton Design Ltd. Design The length of the yacht is and th ...

, 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 23 special wards, wards of Tokyo. The route is ...

in Tokyo, Japan * Mei-Nikan Expressway, route C2 in Nagoya, Japan

Military and aviation

* Command and control, the exercise of authority and direction by a commanding officer * C-2 (poison), developed in the ''Poison laboratory of the Soviet secret services'' * C2A1, Squad Automatic Weapon variant of the FN FAL formerly in Canadian Service * ACAZ C.2, a Belgian prototype fighter aircraft of the 1920s * AEG C.II, a German World War II armed reconnaissance aircraft *

Aeronca C-2 The Aeronca C-2 is an American light monoplane designed by Jean A. Roche and built by Aeronca Aircraft. Development Roche Monoplane Jean A. Roche was a U.S. Army engineer at McCook Field airfield in Dayton, Ohio. Roche developed an aircraft ...

, an American airplane * AGO C.II, a German reconnaissance biplane of World War I * Cierva C.2, a 1921 Spanish experimental autogyro * DFW C.II, a World War I German reconnaissance aircraft *

Fokker C-2 Fokker (; ) was a Dutch aircraft manufacturer that operated from 1912 to 1996. The company was founded by the Dutch aviator Anthony Fokker and became famous during World War I for its fighter aircraft. During its most successful period in the 19 ...

, the American military version of the Fokker F.VII aircraft *

C-2 Greyhound The Grumman C-2 Greyhound is a twin-engine, high-wing cargo aircraft designed to carry supplies, mail, and passengers to and from List of United States Navy aircraft carriers, aircraft carriers of the United States Navy. Its primary mission is ...

, the Grumman cargo aircraft of the United States Navy * , a British C class submarine of the Royal Navy *

Kawasaki C-2 The Kawasaki C-2 (previously XC-2 and C-X) is a mid-size, twin-Turbofan, turbofan engine, long range, high speed military transport aircraft developed and manufactured by Kawasaki Aerospace Company. In June 2016, the C-2 formally entered service ...

, 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, add ...

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

Other

* C2,

UEFA Cup Winners' Cup The UEFA Cup Winners' Cup was a European association football, football club competition contested annually by the winners of domestic cup competitions. The competition's official name was originally the European Cup Winners' Cup; it was renam ...

in football, later merged with UEFA Cup (now

UEFA Europa League The UEFA Europa League (UEL), usually known simply as the Europa League, is an annual association football, football club competition organised since 1971 by the UEFA, Union of European Football Associations (UEFA) for eligible European footb ...

) *

, a film studio *

C-2 visa The C-2 visa is a non-immigrant visa which allows individuals to travel to United States for the purpose of immediate and continuous transit to or from the headquarters of the United Nations, or for United Nations officials transiting the US to a ...

, 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 produced in response to the low-carbohydrate diet trend. This Coke product was marketed as having half the carbohydrates, sugars and calories compared ...

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

Conduit 2 '' Conduit 2'' is a first-person shooter video game developed by High Voltage Software for the Wii video game console. It is the sequel to ''The Conduit''. The definite article of the original title was dropped during development as the develope ...

'', a 2011 first-person shooter video game * AEW Continental Classic, a professional wrestling tournament