X

Universal Words (also x) noun, symbol noun (plural X's, x's ) 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. seealsoXCHROMOSOME, X-RATED, X-RAY symbol 1 the number 10 in ROMANNUMERALS 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 compareTICKn.(1) 5 used to show position, for example on a map: X marks the spot.