X.

名词 x.:

1. the cardinal number that is the sum of nine and one; the base of the decimal system
   同义词：ten, 10, X, tenner, decade
2. the 24th letter of the Roman alphabet
   同义词：X, letter x, ex
3. street names for methylenedioxymethamphetamine
   同义词：Adam, ecstasy, XTC, go, disco biscuit, cristal, X, hug drug

形容词 x.:

1. being one more than nine
   同义词：ten, 10, x