American English

Definition of X noun from the Oxford Advanced American Dictionary



    x (pl. Xs, X's, x's
    jump to other results
  1. 1[countable, uncountable] the 24th letter of the English alphabet “Xylophone” begins with (an) X/“X.”
  2. 2[uncountable] (mathematics) used to represent a number whose value is not mentioned The equation is impossible for any value of x greater than 2.
  3. 3[uncountable] 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
See the Oxford Advanced Learner's Dictionary entry: X