C is the third letter in the Latin alphabet. C or c may also refer to:

Computing

* C (programming language), developed at Bell Labs in 1972 * C, a hexadecimal digit * C, a

computable function Computable functions are the basic objects of study in computability theory. Computable functions are the formalized analogue of the intuitive notion of algorithms, in the sense that a function is computable if there exists an algorithm that can do ...

, the set of all computable decision problems * C:, or "Drive C", the default

drive letter assignment In computer data storage, drive letter assignment is the process of assigning alphabetical identifiers to volumes. Unlike the concept of UNIX mount points, where volumes are named and located arbitrarily in a single hierarchical namespace, dri ...

for the default hard drive in DOS and Windows

Measurement

* °C, Celsius temperature scale * Carat (purity) *

centi- ''Centi'' (symbol c) is a unit prefix in the metric system denoting a factor of one hundredth. Proposed in 1793, and adopted in 1795, the prefix comes from the Latin , meaning "hundred" (cf. century, cent, percent, centennial). Since 1960, the pr ...

, an SI prefix * Coulomb, the SI derived unit for electric charge *

Cup (unit) The cup is a cooking measure of volume, commonly associated with cooking and serving sizes. In the US, it is traditionally equal to . Because actual drinking cups may differ greatly from the size of this unit, standard measuring cups may be use ...

, a unit of volume

Science

Troponin C Troponin C is a protein which is part of the troponin complex. It contains four calcium-binding EF hands, although different isoforms may have fewer than four functional calcium-binding subdomains. It is a component of thin filaments, along wi ...

, one of the three

troponin image:Troponin Ribbon Diagram.png, 400px, Ribbon representation of the human cardiac troponin core complex (52 kDa core) in the calcium-saturated form. Blue = troponin C; green = troponin I; magenta = troponin T.; ; rendered with PyMOL Troponin, ...

s *

Carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

, symbol C, a chemical element *

Atomic carbon Atomic carbon, systematically named carbon and λ0-methane, also called monocarbon, is a colourless gaseous inorganic chemical with the chemical formula C (also written . It is kinetically unstable at ambient temperature and pressure, being remo ...

or C * ATC code C or cardiovascular system, a section of the Anatomical Therapeutic Chemical Classification System *

Haplogroup C (mtDNA) In human mitochondrial genetics, Haplogroup C is a human mitochondrial DNA (mtDNA) haplogroup. Origin Haplogroup C is believed to have arisen somewhere between the Caspian Sea and Lake Baikal some 24,000 years before present. It is a descend ...

, a human mitochondrial DNA (mtDNA) haplogroup *

Haplogroup C-M130 (Y-DNA) Haplogroup C is a major Y-chromosome haplogroup, defined by UEPs M130/RPS4Y711, P184, P255, and P260, which are all SNP mutations. It is one of two primary branches of Haplogroup CF alongside Haplogroup F. Haplogroup C is found in ancient popu ...

, a Y-chromosomal DNA (Y-DNA) haplogroup once called simply C *

Cytosine Cytosine () ( symbol C or Cyt) is one of the four nucleobases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an ...

, nucleic acid * Cysteine * C, a prefix for astronomical objects listed in the

Caldwell catalogue The Caldwell catalogue is an astronomical catalogue of 109 star clusters, nebulae, and galaxies for observation by amateur astronomers. The list was compiled by Patrick Moore as a complement to the Messier catalogue. While the Messier catal ...

, ranging from C1 to C109 * C, a prefix for astronomical star clusters, which follow the IAU's "Chhmm±ddd" format * ''c'', 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 vacuum * ''c'', the speed of sound * ''c'', the

specific heat capacity In thermodynamics, the specific heat capacity (symbol ) of a substance is the heat capacity of a sample of the substance divided by the mass of the sample, also sometimes referred to as massic heat capacity. Informally, it is the amount of heat t ...

of a substance * ''c'', any constant * ''C'',

capacitance Capacitance is the capability of a material object or device to store electric charge. It is measured by the change in charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized ar ...

* C, symbol of coulomb *

Charm quark The charm quark, charmed quark or c quark (from its symbol, c) is the third-most massive of all quarks, a type of elementary particle. Charm quarks are found in hadrons, which are subatomic particles made of quarks. Examples of hadrons containin ...

() *

C-value C-value is the amount, in picograms, of DNA contained within a haploid nucleus (e.g. a gamete) or one half the amount in a diploid somatic cell of a eukaryotic organism. In some cases (notably among diploid organisms), the terms C-value and geno ...

, DNA contained within a haploid nucleus

Technology

C battery The C battery (C size battery or R14 battery) is a standard size of dry cell battery typically used in medium-drain applications such as toys, flashlights, and musical instruments. As of 2007, C batteries accounted for 4% of alkaline primary b ...

, a size of battery *

Capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...

or C * C battery, a type of battery for vacuum tube radios * C or

C-rate A battery charger, recharger, or simply charger is a device that stores energy in a Electric battery, battery by running an electric current through it. The charging protocol (how much voltage or Current source, current for how long, and what to d ...

, a rate of charge and discharge of a battery

Mathematics

* C, a digit meaning twelve in hexadecimal and other positional numeral systems with a radix of 13 or greater * ''C'', the

constant of integration In calculus, the constant of integration, often denoted by C (or c), is a constant term added to an antiderivative of a function f(x) to indicate that the indefinite integral of f(x) (i.e., the set of all antiderivatives of f(x)), on a connected ...

* C, in Roman numerals, the symbol for 100 * C, ℂ, or

\mathbb

, the set of all

complex number In mathematics, a complex number is an element of a number system that extends the real numbers with a specific element denoted , called the imaginary unit and satisfying the equation i^= -1; every complex number can be expressed in the fo ...

s * ℭ or

\mathfrak c

, the cardinality of the continuum * ''C'', the set of continuous functions * The

combination In mathematics, a combination is a selection of items from a set that has distinct members, such that the order of selection does not matter (unlike permutations). For example, given three fruits, say an apple, an orange and a pear, there are th ...

or "choose" function * ''c'' space, the space of all convergent sequences in functional analysis

Music

C (musical note) 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 ...

, and keys based on it: ** C major **

C minor C minor is a minor scale based on C, consisting of the pitches C, D, E, F, G, A, and B. Its key signature consists of three flats. Its relative major is E major and its parallel major is C major. The C natural minor scale is: : Cha ...

* ''

C Album ''C Album'' is the third studio album of the Japanese duo KinKi Kids. It was released on August 4, 1999, and debuted at the top of the Oricon , established in 1999, is the holding company at the head of a Japanese corporate group that supplie ...

'', an album by Kinki Kids * C major chord, a chord in popular music * , symbol used to designate

common time The time signature (also known as meter signature, metre signature, or measure signature) is a notational convention used in Western musical notation to specify how many beats (pulses) are contained in each measure (bar), and which note val ...

* , symbol used to designate

alla breve ''Alla breve'' also known as cut time or cut common timeis a musical meter notated by the time signature symbol (a C with a vertical line through it), which is the equivalent of . The term is Italian for "on the breve", originally meaning th ...

* "C", a composition by Francis Poulenc, one of ''Deux Poèmes de Louis Aragon''

Literature

* ''C'' (novel), a novel by Tom McCarthy * ''C'', a 1924 novel by

Maurice Baring Maurice Baring (27 April 1874 – 14 December 1945) was an English man of letters, known as a dramatist, poet, novelist, translator and essayist, and also as a travel writer and war correspondent, with particular knowledge of Russia. During Wo ...

* ''C Magazine'', a magazine published by

Cardinal Courier Media Cardinal Courier Media, or CCM, is the overseeing body of several media outlets at St. John Fisher College in Pittsford, New York. CCM was founded in 2007 but has roots that date back to 2002. ''Cardinal Courier'' The ''Cardinal Courier'' wa ...

* '' "C" Is for Corpse'', the third novel in Sue Grafton's "Alphabet mystery" series, published in 1986 * C-lehti ('C-magazine'), a defunct Finnish computer magazine

Transportation

* NZR C class (1873) train * NZR C class (1930) train * C, or 0-6-0 classification, a type of locomotive with three powered axles *C, the unofficial designation used by the U.S. Navy classification for

Protected Cruisers Protected cruisers, a type of naval cruiser of the late-19th century, gained their description because an armoured deck offered protection for vital machine-spaces from fragments caused by shells exploding above them. Protected cruisers r ...

and Peace Cruisers before the 1920 reclassification. *

C (Los Angeles Railway) C refers to two streetcar routes in Los Angeles, California. The lines were operated by the Los Angeles Railway from 1910 to 1932. History Angeleno Heights and Crown Hill (1910–1923) The beginnings of the route begin in 1910 when the Los Ang ...

C (New York City Subway service) The C Eighth Avenue Local is a rapid transit service in the B Division of the New York City Subway. Its route emblem, or "bullet", is since it uses the IND Eighth Avenue Line in Midtown Manhattan. The C operates at all times except late nigh ...

C Line (Los Angeles Metro) The C Line (formerly the Green Line from 1995 to 2020) is a light rail line running between Redondo Beach and Norwalk within Los Angeles County. It is one of seven lines forming the Los Angeles Metro Rail system, and opened on August 12, 19 ...

* Line C of the Buenos Aires Subte

Sport

* Captain (ice hockey) *

Catcher Catcher is a position in baseball and softball. When a batter takes their turn to hit, the catcher crouches behind home plate, in front of the ( home) umpire, and receives the ball from the pitcher. In addition to this primary duty, the ca ...

, a position in baseball * Center (basketball) * Center (gridiron football)

Other uses

* Prefix "c", to specify a

column number In typography, a column is one or more vertical blocks of content positioned on a page, separated by gutters (vertical whitespace) or rules (thin lines, in this case vertical). Columns are most commonly used to break up large bodies of text that ...

as in-source-locator in old citations * С, a letter of the Cyrillic alphabet * ''C'' (anime), by Tatsunoko Production, Fuji TV * C (grade), a satisfactory grade in education * C (plastic toy), a plastic toy from former Czechoslovakia * Citigroup, Inc.'s stock ticker symbol *

Gaius Gaius, sometimes spelled ''Gajus'', Kaius, Cajus, Caius, was a common Latin praenomen; see Gaius (praenomen). People * Gaius (jurist) (), Roman jurist *Gaius Acilius *Gaius Antonius *Gaius Antonius Hybrida *Gaius Asinius Gallus *Gaius Asinius P ...

or C * Center Party (Sweden), a Swedish political party *

Mansfield Smith-Cumming Captain Sir Mansfield George Smith-Cumming (1 April 1859 – 14 June 1923) was a British naval officer who served as the first chief of the Secret Intelligence Service (SIS). Origins He was a great-great grandson of the prominent merchant John ...

or C (1859–1923), Chief of the SIS, the UK Secret Intelligence Service, also known as MI6 ** His successors as Chief of the SIS have since been generally known by his alias, C * C, also known as Max Denbigh, a character played by Andrew Scott in the film ''

Spectre Spectre, specter or the spectre may refer to: Religion and spirituality * Vision (spirituality) * Apparitional experience * Ghost Arts and entertainment Film and television * ''Spectre'' (1977 film), a made-for-television film produced and writ ...

'' * c (IPA) in the International Phonetic Alphabet (IPA), the voiceless palatal stop * Dominical letter C for a common year starting on Friday * C, the production code for the 1964 ''Doctor Who'' serial ''

The Edge of Destruction ''The Edge of Destruction'' (also referred to as ''Inside the Spaceship'') is the third serial of the British science fiction television series '' Doctor Who''. It was written by David Whitaker, and first broadcast on BBC TV in two weekly part ...

'' * Charlie, the military time zone code for UTC+03:00 * c, alternative name for

Grimes Claire Elise Boucher (; born March 17, 1988), known professionally as Grimes, is a Canadian musician, singer, songwriter, and record producer. Her early work has been described as extending from "lo-fi R&B" to futuristic dance-pop, and has i ...

Farmall C The Farmall C is a small two-plow row crop tractor produced by International Harvester under the Farmall brand from 1948 to 1951. The C was developed from the Farmall B as a slightly larger, more versatile implement, raising and moving the B's ...

, a tractor produced by International Harvester from 1948 to 1951 * C (restaurant), a restaurant in Tampere, Finland