Synonyms of X

What is another word for X
1.

Synonyms of X

noun - the cardinal number that is the sum of nine and one

TEN 
   

noun - the 24th letter of the Roman alphabet

EX 

noun - street names for methylenedioxymethamphetamine

XTC 
GO 

adj - being one more than nine

TEN 
   
2.

Synonyms of X