to cross out or mark with or as if with an x (often followed byout ).
to x out an error.
to indicate choice, as on a ballot or examination (often followed byin ).
to x in the candidate of your choice.
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 .
(used at the end of letters, telegrams, etc., to indicate a kiss.)
(used to indicate multiplication) times.
8 × 8=64.
(used between figures indicating dimensions) by.
3″ × 4″ (read: “three by four inches”);
3″ × 4″ × 5″ (read: “three by four by five inches”).
power of magnification.
a 50x telescope.
(used as a signature by an illiterate person.)
cross.
crossed with.
(used to indicate a particular place or point on a map or diagram).
X marks the spot where the pirates' treasure is buried.
out of; foaled by.
a colt by Flag-a-way x Merrylegs.
(used to indicate choice, as on a ballot, examination, etc.)
(used to indicate an error or incorrect answer, as on a test.)
Mathematics. (in Cartesian coordinates) the x-axis.
Chess. captures.
a person, thing, agency, factor, etc., of unknown identity.
I feel sorry for poor Mr. X, the man she will ultimately marry.
the 24th letter of the English alphabet, a consonant.
any spoken sound or combination of sounds represented by the letter X or x, as in xylene, box, or exact.
something having the shape of an X .
a written or printed representation of the letter X or x.
a device, as a printer's type, for reproducing the letter X or x.
experimental.
extra.
extraordinary.
the 24th in order or in a series.
(sometimes lowercase) the Roman numeral for 10.
Christ.
Christian.
cross.
Electricity. reactance.
Slang. a ten-dollar bill.
(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.
(in Great Britain) a designation for a film recommended for adults only.
a person, thing, agency, factor, etc., of unknown identity.
Chemistry. (formerly) xenon.
indicating a film that may not be publicly shown to anyone under 18. Since 1982 replaced by symbol 18
( as modifier )
an X film
denoting any unknown, unspecified, or variable factor, number, person, or thing
(on letters, cards, etc) denoting a kiss
(on ballot papers, etc) indicating choice
(on examination papers, etc) indicating error
for Christ; Christian
ten See Roman numerals
commerce banking finance ex
maths the x- axis or a coordinate measured along the x- axis in a Cartesian coordinate system
an algebraic variable
the 24th letter and 19th consonant of the modern English alphabet
a speech sound sequence represented by this letter, in English pronounced as ks or gz or, in initial position, z, as in xylophone
First recorded in 1840–50
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
For his readers, Mr. Elwes makes this number more manageable with another tool, exponentiation: There are 107 x 1060 = 1067 monkeys.
From The Wall Street Journal • May 29, 2026
After the call, Wilson sent Ghost a text, which was shown to the court, that read: "Charlotte says all good. She just meant 'it was a bizarre situation' not that she felt personally uncomfortable x."
From BBC • May 8, 2026
It’s sort of like if Andy Warhol slapped his name on a can of Campbell’s soup — Warhol x Campbell’s Chicken & Stars — instead of painting them as pop art.
From Salon • Apr. 20, 2026
After all, does it get any more L.A. niche than a Bob Baker x Ben Platt x Addison Rae Coachella crossover?
From Los Angeles Times • Apr. 16, 2026
I write 10, 28, 54, not, as the Romans did, x, xxviii, liv.
From "The Invention of Science" by David Wootton
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
