I. ˈeks noun
( plural x's or xs or x'es or xes ˈeksə̇z)
Usage: often capitalized, often attributive
1.
a. : the 24th letter of the English alphabet
b. : an instance of this letter printed, written, or otherwise represented
c. : a speech counterpart of orthographic x (as x in xylophone, extra, next, or ox )
2. : ten — see number table
3. : a printer's type, a stamp, or some other instrument for reproducing the letter x
4. : someone or something arbitrarily or conveniently designated x: as
a. : the 24th in order or class
b. : the 23d in order or class when j is not used
c. : the 21st in order or class when j, v, and w are not used
d. : the first in an order or class including x, y, and sometimes z
5.
a. : unknown quantity 1
find the value of x in the equation x -4 2 =3
b. : an arbitrarily chosen value from the domain of a variable
in the equation y=x 2 , let x =4
c. : x-coordinate
6.
a. : something (as a cross) having the shape of the letter X
b. : something (as a $10 bill) marked with an X
7.
[so called from the use of the letter in crossing out mistakes in writing]
: something (as a statement, answer, or result) that is wrong : mistake , error
8. x's plural , often capitalized : atmospherics 1
9. : the basic or monoploid number of chromosomes of a polyploid series : the number contained in a single genome — compare n
II. transitive verb
( x-ed also x'd or xed ; x-ed also x'd or xed ˈekst ; x-ing or x'ing ˈeksiŋ ; x'es or xes ˈeksə̇z)
1. : to mark with an x
x-ed his ballot clearly
2. : to cancel or obliterate with or as if with a series of x's — usually used with out
x-ing out most of what he had written
III. abbreviation
Usage: often capitalized
1. cross
2. ex
3. experimental
4. extra
5. xenon
IV. symbol
1. unknown quantity
2.
a. times : by
b. hybrid
the license reads Dachshund x
a tall willow ( Salix x blanda ) developed in cultivation
: hybridity
c. out of
a litter by a grade sire x a scrub dam
3. capitalized
[from the Greek letter X]
Christ : Christian
4. power of magnification
5. capitalized reactance
6. abscissa
7. crossed with
8. kiss
9. a playing card of low rank
10. capitalized chemical group — used especially of a univalent anion or typically univalent negative radical (as halogen) in general formulas
11. the person in question — used especially by an illiterate in place of a signature
12. the place in question — used on a map or picture
13. — used to indicate choice or approval (as on a ballot)
V. ˈeks adjective
Usage: usually capitalized
of a motion picture : of such a nature that admission is denied to persons under a specified age (as 17) — used before the adoption of NC-17