Main definitions of X in English

: X1X2X3

X1

(also x)

noun

  • 1The twenty-fourth letter of the alphabet.

    • ‘The Latin X came from Chi, a letter invented by the Greeks who used it to represent the sound ks in the Western part of the country.’
    • ‘X is the 24th letter of the alphabet and it's got me stumped.’
    1. 1.1 Denoting the next after W in a set of items, categories, etc.
      • ‘A participant may answer a multiple-choice question with either the letter answer (W, X, Y or Z) or the verbal answer; however, if the verbal answer is given, it must be exactly as indicated in the question.’
      • ‘You give the variable operand one of the 4 names #W, #X, #Y, or #Z.’
    2. 1.2 Denoting an unknown or unspecified person or thing.
      ‘there is nothing in the data to tell us whether X causes Y or Y causes X’
      • ‘A greater number of fresh vegetables are sold in City X than in City Y.’
      • ‘Regarding Mr. X's remarks about the Directorate of Operations' "pitiful management": I did describe in my article the problem of upwardly mobile mediocrity, but Mr. X is right to fault me for not hammering home the point.’
      • ‘Discover how 'Mr X' built an online business making over $100,000 a month (mostly profit) in just 16 weeks.’
    3. 1.3"x" (in describing play in bridge) denoting an unspecified card other than an honour.
      ‘East knows that declarer cannot hold a doubleton Qx’
      • ‘In this case we are comparing the chances of East having J-10-x, J-x, or 10-x.’
      • ‘If your doubleton suit is in the form of: K Q, K J, Q J, Q x, J x don't count both honor and Shape points.’
    4. 1.4usually "x" The first unknown quantity in an algebraic expression, usually the independent variable.
      • ‘For the quadratic function y=X^ - 9, determine the values of X such that y>or equal to 7.’
      • ‘We express a relationship between two variables, which we will refer to as x and y, by stating the following: The value of the variable y depends upon the value of the variable x.’
    5. 1.5usually "x" Denoting the principal or horizontal axis in a system of coordinates.
      in combination ‘the x-axis’
      • ‘Click on the Options tab; then choose XY Plot and select the signal to be used for X coordinate generation in the X-Axis box.’
      • ‘When displaying two variables in a time domain plot, the X-axis is labeled with units of time.’
  • 2A shape like that of a letter X.

    ‘two wires in the form of an X’
    in combination ‘an X-shaped cross’
    • ‘Way back in the days of snail mail, teenagers would put an X across the envelope seal of a love letter to discourage the courier (usually a friend) from opening the envelope to take a peek (there was no guarantee that the envelope could be re-sealed with the X accurately realigned).’
    • ‘As a compromise, management marked each of the Idles' hands with a large black "X" as a warning to the club's staff not to serve alcohol to the band.’
    • ‘The design of the Exofit safety harness uses a single piece of material constructed in the shape of an "X" that wraps around the worker.’
    • ‘These conditions are normally very difficult to achieve, but we can reproduce these conditions by using two (or more) fine wires arranged so that they cross and touch at a single point, in the form of an X, as the load of a pulsed power generator.’
    • ‘Also there were two paragraphs edited out with XXX's over them which were not initialed by either of us.’
  • 3A cross-shaped written symbol.

    1. 3.1 Used to indicate a position on a map or diagram.
      ‘put an X on the spot where you think its eye should be’
      • ‘In Sweden, X is used by the armed forces on maps to denote that blasting or other type of destruction has been prepared.’
      • ‘If you happen to camp just North of the straight trail section, the only way to accurately place the X on the map is to use a GPS.’
      • ‘The landing site, marked by a red "X", is located at 192.3 degrees west, 10.3 degrees south.’
      • ‘The students are to use the map to find the sites marked with an X.’
    2. 3.2 Used to indicate a mistake or incorrect answer.
      • ‘Mark incorrect responses with an X.’
      • ‘I put a check next to correct problems and an X by incorrect problems.’
    3. 3.3 Used in a letter or message to symbolize a kiss.
      • ‘Have a lovely day! xxxxx’
      • ‘Take care, love, Raffa xxx’
    4. 3.4 Used to indicate one's vote on a ballot paper.
      ‘with trembling hand you inscribe your X on the slip of paper’
      • ‘In order to vote you simply put an 'X' next to the name of the candidate you support.’
      • ‘Voters mark an 'X' in the first column for their first choice and a second 'X' in the second column for their other choice.’
    5. 3.5 Used in place of the signature of a person who cannot write.
      ‘nearly all those engaged in the fur trade signed with an X’
      • ‘In many jurisdictions testators may authenticate their last will and testament with the letter X’
      • ‘In other states the law requires courts to invalidate wills that are signed with an X unless the testator was physically or mentally incapable of signing her full name.’
      • ‘When a person is physically unable to sign his or her name on the voter registration form, he or she may mark an X or take an oath swearing to the statement on the form.’
      signature, autograph, cross, scribble, squiggle, initials, imprint
      View synonyms
  • 4The Roman numeral for ten.

    • ‘These inscriptions allow us to demonstrate the presence of seven cohorts of the legion, either in whole or part, building on Hadrian's Wall: cohorts I, II, III, VI, VII, VIII and X.’
    • ‘IX means to subtract I from X, leaving 9.’
    • ‘One theory maintains that only the centurions of the first cohort, the so-called primi ordines, had different ranks, while the centurions of cohorts II-X all ranked equally.’
    • ‘So XXXI is 31, and XXIV is 24.’

Pronunciation

X

/ɛks/

Main definitions of X in English

: X1X2X3

X2

  • A rating assigned to films classified as suitable for adults only (replaced in the UK in 1983 by 18, and in the US in 1990 by NC–17).

Pronunciation

X

/ɛks/

Main definitions of X in English

: X1X2X3

X3

abbreviation

North American
informal
  • The drug ecstasy.

    • ‘They also appreciated that using "X" took them away from normal everyday problems.’
    • ‘Many of the users reported that, since "X" only lasts 4 to 5 hours, it brought them the feeling they wanted, and yet they were still able to control themselves unlike with other drugs such as LSD which has a longer duration.’
    • ‘I had just turned 18 and we went to a dance club, and my friends all got some "X".’

Pronunciation

X

/ɛks/