[ eks ]

verb (used with object),x-ed or x'd [ekst], /ɛkst/, x-ing or x'ing [ek-sing]. /ˈɛk sɪŋ/.
  1. to cross out or mark with or as if with an x (often followed by out): to x out an error.

  2. to indicate choice, as on a ballot or examination (often followed by in): to x in the candidate of your choice.

Origin of x

First recorded in 1840–50

Words Nearby x

Other definitions for x (2 of 6)


  1. Stock Exchange.

Other definitions for x (3 of 6)


  1. an unknown quantity or a variable.

    • the letter x used to replace or obscure a gender morpheme, as to avoid the -o or -a inflection of a word borrowed from Spanish or the sequence m-e-n in the word women. See Latinx, womxn.

    • the letter x indicating a variable and used to hold a place in a word or abbreviation that can be occupied by another letter, as in CxO to account for a range of specialized executive positions in a corporation, for example CEO, CFO, and COO.

  1. (used at the end of letters, telegrams, etc., to indicate a kiss.)

  2. (used to indicate multiplication) times: 8 × 8=64.

  3. (used between figures indicating dimensions) by:3″ × 4″ (read: “three by four inches”);3″ × 4″ × 5″ (read: “three by four by five inches”).

  4. power of magnification: a 50x telescope.

  5. (used as a signature by an illiterate person.)

  6. cross.

  7. crossed with.

  8. (used to indicate a particular place or point on a map or diagram): X marks the spot where the pirates' treasure is buried.

  9. out of; foaled by: a colt by Flag-a-way x Merrylegs.

  10. (used to indicate choice, as on a ballot, examination, etc.)

  11. (used to indicate an error or incorrect answer, as on a test.)

  12. Mathematics. (in Cartesian coordinates) the x-axis.

  13. Chess. captures.

  14. a person, thing, agency, factor, etc., of unknown identity: I feel sorry for poor Mr. X, the man she will ultimately marry.

Other definitions for X (4 of 6)


or x

[ eks ]

noun,plural X's or Xs, x's or xs.
  1. the 24th letter of the English alphabet, a consonant.

  2. any spoken sound or combination of sounds represented by the letter X or x, as in xylene, box, or exact.

  1. something having the shape of an X.

  2. a written or printed representation of the letter X or x.

  3. a device, as a printer's type, for reproducing the letter X or x.

Other definitions for X (5 of 6)


  1. experimental.

  2. extra.

  1. extraordinary.

Other definitions for X (6 of 6)


  1. the 24th in order or in a series.

  2. (sometimes lowercase) the Roman numeral for 10.: Compare Roman numerals.

  1. Christ.

  2. Christian.

  3. cross.

  4. Electricity. reactance (def. 1).

  5. Slang. a ten-dollar bill.

  6. (no longer in official use by the Motion Picture Association of America) a rating for movies with subject matter that is suitable for adults only.

  7. (in Great Britain) a designation for a film recommended for adults only.: Compare A3 (def. 10), AA2 (def. 5), U5 (def. 6).

  8. a person, thing, agency, factor, etc., of unknown identity.

  9. Chemistry. (formerly) xenon.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use x in a sentence

British Dictionary definitions for x (1 of 3)



/ (ɛks) /

nounplural x's, X's or Xs
  1. the 24th letter and 19th consonant of the modern English alphabet

  2. a speech sound sequence represented by this letter, in English pronounced as ks or gz or, in initial position, z, as in xylophone

British Dictionary definitions for x (2 of 3)


symbol for
  1. commerce banking finance ex

  2. maths the x- axis or a coordinate measured along the x- axis in a Cartesian coordinate system

  1. an algebraic variable

British Dictionary definitions for X (3 of 3)


symbol for
  1. (formerly, in Britain)

    • indicating a film that may not be publicly shown to anyone under 18. Since 1982 replaced by symbol 18

    • (as modifier): an X film

  2. denoting any unknown, unspecified, or variable factor, number, person, or thing

  1. (on letters, cards, etc) denoting a kiss

  2. (on ballot papers, etc) indicating choice

  3. (on examination papers, etc) indicating error

  4. for Christ; Christian

  5. (Roman numeral) ten: See Roman numerals

Origin of X

(sense 6) from the form of the Greek letter khi (Χ), first letter of Khristos Christ

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