Main definitions of X in English

: X1X2

X1

(also x)

noun

  • 1The twenty-fourth letter of the alphabet.

    • ‘X is the 24th letter of the alphabet and it's got me stumped.’
    • ‘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.’
    1. 1.1Denoting 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. 1.2Denoting an unknown or unspecified person or thing.
      ‘there is nothing in the data to tell us whether X causes Y or Y causes X’
      • ‘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.’
      • ‘A greater number of fresh vegetables are sold in City X than in City Y.’
      • ‘Discover how 'Mr X' built an online business making over $100,000 a month (mostly profit) in just 16 weeks.’
    3. 1.3(used in describing play in bridge) denoting an unspecified card other than an honor.
      • ‘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.’
      • ‘In this case we are comparing the chances of East having J-10-x, J-x, or 10-x.’
    4. 1.4The 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. 1.5Denoting the principal or horizontal axis in a system of coordinates.
      • ‘When displaying two variables in a time domain plot, the X-axis is labeled with units of time.’
      • ‘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.’
  • 2A cross-shaped written symbol, in particular.

    1. 2.1Used to indicate a position on a map or diagram.
      • ‘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. 2.2Used 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. 2.3Used in a letter or message to symbolize a kiss.
      • ‘Take care, love, Raffa xxx’
      • ‘Have a lovely day! xxxxx’
    4. 2.4Used to indicate one's vote on a paper ballot.
      • ‘Voters mark an 'X' in the first column for their first choice and a second 'X' in the second column for their other choice.’
      • ‘In order to vote you simply put an 'X' next to the name of the candidate you support.’
    5. 2.5Used in place of the signature of a person who cannot write.
      • ‘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.’
  • 3A 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).’
    • ‘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.’
    • ‘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.’
    • ‘Also there were two paragraphs edited out with XXX's over them which were not initialed by either of us.’
    • ‘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.’
  • 4The Roman numeral for ten.

    • ‘IX means to subtract I from X, leaving 9.’
    • ‘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.’
    • ‘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.’

verb

[WITH OBJECT]
  • 1 Mark or make a sign with an X.

    • ‘Try yellow highlighter X'd on the inside window as one big X or several little X's.’
    • ‘Another day X'ed on my calender.’
    1. 1.1Overwrite or obliterate with an X or series of X's.
      • ‘There are hand-written notes and corrections, done in pencil; in some places whole blocks of text are stricken out, x'd over with a typewriter or opaqued with red crayon.’
      • ‘Also can he go to court and say that the XXX'd over paragraphs are still valid?’
    2. 1.2Make void or annul; invalidate.
      ‘we're all X-ing things out of our curricula’
      • ‘X is for X-ing out accidents in your home.’
      • ‘In the latest case study from the SA2 Author Experience File, one author reports X-ing out an unacceptable provision and mailing the contract back for the publisher's agent to sign.’
      • ‘Uh, I found more but then accidentally Xed out the page and I'm too lazy to bring it back up.’
      • ‘We're talking about a savings of some $20 million per year alone just by x-ing out this non-essential department completely.’

Pronunciation:

X

/eks/

Main definitions of X in English

: X1X2

X2

  • 1A rating assigned to movies classified as suitable for adults only.

    Replaced in 1990 by NC-17
  • 2(in systematic names of organisms) hybrid.

Pronunciation:

X

/eks/