X

Ⅰ.

X [1] (also x) ► NOUN (pl. Xs or X's) 1) the twenty-fourth letter of the alphabet. 2) denoting an unknown or unspecified person or thing. 3) the first unknown quantity in an algebraic expression. 4) referring to the principal or horizontal axis in a system of coordinates. 5) a cross-shaped written symbol, used to indicate an incorrect answer or to symbolize a kiss. 6) the Roman numeral for ten.

Ⅱ.

X [2] ► SYMBOL ▪ films classified as suitable for adults only (replaced in the UK in 1983 by 18, and in the US in 1990 by NC 17).