1.the 24th letter of the English alphabet. X is a consonant.
2.the roman numeral for 10
3.used in mathematics for showing a number whose value you do not know
4.used instead of saying the name of a person or place when you do not know it, or when you are using them as an example
5.a symbol used for writing a kiss, usually at the end of a letter
6.used in the past for saying that a movie was not appropriate for people under the age of 18