(also x ) / eks; NAmE / noun , symbol
■ noun ( pl. Xs , X's , x's / ˈeksɪz; NAmE /)
1.
[ C , U ] the 24th letter of the English alphabet :
'Xylophone' begins with (an) X / 'X'.
2.
[ U ] ( mathematics ) used to represent a number whose value is not mentioned :
The equation is impossible for any value of x greater than 2.
3.
[ U ] a person, a number, an influence, etc. that is not known or not named :
Let's suppose X knows what Y is doing.
—see also X chromosome , X-rated , X-ray
■ symbol
1.
the number 10 in Roman numerals
2.
used to represent a kiss at the end of a letter, etc. :
Love from Kathy XXX.
3.
used to show a vote for sb in an election :
Write X beside the candidate of your choice.
4.
used to show that a written answer is wrong
—compare tick noun (1)
5.
used to show position, for example on a map :
X marks the spot.