x

1 of 5

noun

plural x's or xs ˈek-səz How to pronounce x (audio)
often capitalized, often attributive
1
a
: the 24th letter of the English alphabet
b
: a graphic representation of this letter
c
: a speech counterpart of orthographic x
2
3
: a graphic device for reproducing the letter x
4
: one designated x especially as the 24th in order or class, or the first in an order or class that includes x, y, and sometimes z
5
: an unknown quantity
6
: something shaped like or marked with the letter X

x

2 of 5

verb

x-ed also x'd or xed ˈekst How to pronounce x (audio) ; x-ing or x'ing ˈek-siŋ How to pronounce x (audio)

transitive verb

1
: to mark with an x
2
: to cancel or obliterate with a series of x's
usually used with out
x-ed out the mistake

x

3 of 5

abbreviation

1
cross
2
ex
3
experimental
4
extra

x

4 of 5

symbol

1
a
times
2 x 3 = 6
The picture was enlarged 3x [=enlarged to three times the original size].
b
by
used in measurements
an 8x11 sheet of paper
An early 20th century Persian Hamadan Gallery carpet with a camel hair ground, measuring 10.10 x 5.5.The Magazine Antiques
2
by
used in nonmathematical constructions
He drove a 4x4 vehicle.

X

5 of 5

adjective

of a motion picture
: of such a nature that admission is denied to persons under a specified age (such as 17)
used before the adoption of NC-17

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Words Starting With X

Browse 436 words and phrases that start with the letter X, from Xanadu to xystus.

Examples of x in a Sentence

Noun a word that starts with an x a word that starts with x

Word History

First Known Use

Noun

before the 12th century, in the meaning defined at sense 1a

Verb

circa 1849, in the meaning defined at sense 1

Adjective

1970, in the meaning defined above

Time Traveler
The first known use of x was before the 12th century

Dictionary Entries Near x

Cite this Entry

“X.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/x. Accessed 4 Mar. 2024.

Kids Definition

x

1 of 3 noun
often capitalized
1
: the 24th letter of the English alphabet
2
: ten in Roman numerals
3
: an unknown quantity

x

2 of 3 verb
x-ed also x'd or xed ˈekst How to pronounce x (audio) ; x-ing or x'ing ˈek-siŋ How to pronounce x (audio)
1
: to mark with an x
2
: to cancel with a series of x's

X

3 of 3 adjective
of a motion picture
: of such a nature that admission is denied to persons under a certain age (as 17)
used before the adoption of NC-17

Medical Definition

x

1 of 2 noun
plural x's or xs or x'es or xes ˈek-səz How to pronounce x (audio)
: the basic or monoploid number of chromosomes of a polyploid series : the number contained in a single genome compare n sense 1

x

2 of 2 symbol
1
capitalized halogen atom
used in general formulas (as of trihalomethane CHX3)
2
power of magnification

Legal Definition

x

1 of 2 noun
often capitalized
1
: a mark used in place of a signature when the maker is incapable of signing his or her name (as because of illiteracy or a physical ailment)
2
: a mark used in indicating a choice or applicable item (as on an insurance form)

x

2 of 2 abbreviation
1
ex-distribution
2
ex-dividend
3
ex-rights
4
ex-warrants

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