# C (disambiguation)

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, the set of all computable decision problems
* C:, or "Drive C", the default drive letter assignment for the default hard drive in DOS and Windows

## Measurement

* °C, Celsius temperature scale
* Carat (purity)
* centi-, an SI prefix
* Coulomb, the SI derived unit for electric charge
* Cup (unit), a unit of volume

## Science

* Troponin C, one of the three troponins
* Carbon, symbol C, a chemical element
* Atomic carbon or C
* ATC code C or cardiovascular system, a section of the Anatomical Therapeutic Chemical Classification System
* Haplogroup C (mtDNA), a human mitochondrial DNA (mtDNA) haplogroup
* Haplogroup C-M130 (Y-DNA), a Y-chromosomal DNA (Y-DNA) haplogroup once called simply C
* Cytosine, nucleic acid
* C (or Cys), an abbreviation for the amino acid cysteine
* C, a prefix for astronomical objects listed in the Caldwell catalogue, 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 in vacuum
* c, the speed of sound
* c, the specific heat capacity of a substance
* c, any constant
* C, capacitance
* C, symbol of coulomb
* Charm quark ( c )
* C-value, DNA contained within a haploid nucleus

## Technology

* C battery, a size of battery
* Capacitor or C
* C battery, a type of battery for vacuum tube radios
* C or C-rate, 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
* C, in Roman numerals, the symbol for 100
* C, $\mathbb {C}$, or $\mathbb {C}$, the set of all complex numbers
* ℭ or ${\mathfrak {c}}$, the cardinality of the continuum
* C, the set of continuous functions
* The combination or "choose" function
* c space, the space of all convergent sequences in functional analysis

## Music

* C (musical note), and keys based on it:
** C major
** C minor
* C Album, an album by Kinki Kids
* C major chord, a chord in popular music
* , symbol used to designate common time
* , symbol used to designate alla breve
* "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
* C Magazine, a magazine published by Cardinal Courier Media
* "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

* Mercedes-Benz C-class
* 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 and Peace Cruisers before the 1920 reclassification.
* C (Los Angeles Railway)
* C (S-train) a service on the S-train network in Copenhagen
* C (New York City Subway service)
* C Line (Los Angeles Metro)
* Line C of the Buenos Aires Subte
* Tokyo Metro Chiyoda Line, a subway service operated by the Tokyo Metro, labeled
* Chūō Line, a subway service operated by the Osaka Metro, labeled
* RER C, a line in the RER of Paris
* The official West Japan Railway Company service symbol for:
** Kusatsu Line.
** Sakai Line.

## Sport

* Captain (ice hockey)
* Catcher, a position in baseball
* Center (basketball)
* Center (gridiron football)

## Other uses

* Prefix "c", to specify a column number 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 or C
* Center Party (Sweden), a Swedish political party
* Mansfield Smith-Cumming 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
* 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
* Charlie, the military time zone code for UTC+03:00
* c, alternative name for Grimes
* Farmall C, a tractor produced by International Harvester from 1948 to 1951
* C (restaurant), a restaurant in Tampere, Finland