or c.

  1. (with a year) about: c1775.

Origin of c

From Latin circā, circiter, circum

Words Nearby c

Other definitions for c (2 of 13)


  1. Optics. candle; candles.

  2. cycle; cycles.

Other definitions for c (3 of 13)


  1. Physics, Optics. the speed of light in a vacuum: standardized as 186,282.4 miles per second (299,792,458 meters per second).

  2. Physics, Acoustics. the speed of sound.

Other definitions for c̄ (4 of 13)

  1. (in prescriptions) with.

Origin of c̄

From the Latin word cum

Other definitions for c≻ (5 of 13)


  1. capitals and small capitals.

Other definitions for C (6 of 13)


or c

[ see ]

noun,plural C's or Cs, c's or cs.
  1. the third letter of the English alphabet, a consonant.

  2. any spoken sound represented by the letter C or c, as in cat, race, or circle.

  1. something having the shape of a C.

  2. a written or printed representation of the letter C or c.

  3. a device, as a printer's type, for reproducing the letter C or c.

Other definitions for C (7 of 13)


  1. Computers. a high-level programming language: very powerful and flexible, it is used in a wide variety of applications.

Other definitions for C (8 of 13)


  1. Electricity. coulomb.

  2. county (used with a number to designate a county road): C55.

Other definitions for C (9 of 13)


  1. the third in order or in a series.

  2. (in some grading systems) a grade or mark, as in school or college, indicating the quality of a student's work as fair or average.: Sometimes c

  1. Music.

    • the first tone, or keynote, in the scale of C major or the third tone in the relative minor scale, A minor.

    • a string, key, or pipe tuned to this tone.

    • a written or printed note representing this tone.

    • (in the fixed system of solmization) the first tone of the scale of C major, called do.

    • the tonality having C as the tonic note.

    • a symbol indicating quadruple time and appearing after the clef sign on a musical staff.

  2. the Roman numeral for 100.: Sometimes c

  3. Electricity.

    • a battery size for 1.5 volt dry cells: diameter, 1 inch (2.5 centimeters); length, 1.9 inches (4.8 centimeters).

  4. Chemistry. carbon (def. 1).

  5. Physics.

  6. Biochemistry.

  7. Also C-note. Slang. a hundred-dollar bill.

  8. a proportional shoe width size, narrower than D and wider than B.

  9. a proportional brassiere cup size, smaller than D and larger than B.

  10. the lowest quality rating for a corporate or municipal bond.

Other definitions for C- (10 of 13)


U.S. Military.
  1. (in designations of transport aircraft) cargo: C-54; C-124.

Other definitions for c. (11 of 13)


  1. gallon.

Origin of c.

From the Latin word congius

Other definitions for c. (12 of 13)


  1. Optics. candle; candles.: Also c

  2. carat.

  1. carbon.

  2. carton.

  3. case.

  4. Baseball. catcher.

  5. cathode.

  6. cent; cents.

  7. centavo.

  8. Football. center.

  9. centigrade.

  10. centime.

  11. centimeter.

  12. century.

  13. chairman; chairperson.

  14. chapter.

  15. chief.

  16. child.

  17. church.

  18. cirrus.

  19. city.

  20. cloudy.

  21. cognate.

  22. color.

  23. copper.

  24. copyright.

  25. corps.

  26. cubic.

  27. cycle; cycles.: Also c

Other definitions for C. (13 of 13)


  1. Calorie.

  2. Cape.

  1. Catholic.

  2. Celsius.

  3. Celtic.

  4. Centigrade.

  5. College.

  6. (in Costa Rica and El Salvador) colon; colons.

  7. Congress.

  8. Conservative.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use c in a sentence

British Dictionary definitions for c (1 of 7)


symbol for
  1. centi-

  2. cubic

  1. cycle

  2. maths constant

  3. specific heat capacity

  4. the speed of light and other types of electromagnetic radiation in a vacuum

British Dictionary definitions for c (2 of 7)



/ (siː) /

nounplural c's, C's or Cs
  1. the third letter and second consonant of the modern English alphabet

  2. a speech sound represented by this letter, in English usually either a voiceless alveolar fricative, as in cigar, or a voiceless velar stop, as in case

  1. the third in a series, esp the third highest grade in an examination

    • something shaped like a C

    • (in combination): a C-spring

British Dictionary definitions for C (3 of 7)


symbol for
  1. music

    • a note having a frequency of 261.63 hertz (middle C) or this value multiplied or divided by any power of 2; the first degree of a major scale containing no sharps or flats (C major)

    • a key, string, or pipe producing this note

    • the major or minor key having this note as its tonic

    • a time signature denoting four crotchet beats to the bar: See also alla breve (def. 2), common time

  2. chem carbon

  1. biochem cytosine

  2. capacitance

  3. heat capacity

  4. cold (water)

  5. physics compliance

  6. Celsius

  7. centigrade

  8. century: C20

  9. coulomb

  10. (Roman numeral) 100: See Roman numerals

abbreviation for
  1. Cuba (international car registration)

  1. a computer programming language combining the advantages of a high-level language with the ability to address the computer at a level comparable with that of an assembly language

British Dictionary definitions for C- (4 of 7)


abbreviation for(of US military aircraft)
  1. cargo transport: C-5

British Dictionary definitions for c. (5 of 7)


abbreviation for
  1. carat

  2. cricket caught

  1. cent(s)

  2. century or centuries

  3. (used esp preceding a date) circa: c. 1800

Origin of c.

(for sense 5) Latin: about

British Dictionary definitions for C. (6 of 7)


abbreviation for
  1. (on maps as part of name) Cape

  2. Catholic

  1. Celtic

  2. Conservative

  3. Corps

British Dictionary definitions for c/- (7 of 7)


abbreviation forAustralian (in addresses)
  1. care of

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for c (1 of 2)


  1. The symbol for the speed of light in a vacuum.

Scientific definitions for C (2 of 2)


  1. Abbreviation of capacitance, capacitor, capacity, Celsius, charge conjugation, coulomb, cytosine

  1. A programming language developed in 1972 and commonly used for writing professional software. With only a small number of built-in functions, it requires less memory than other languages, and because most if its functions are not specific to particular computers, it can be used on many different kinds of machines. The Unix operating system was written in C.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.