X vs es

X

noun
  • Any mark that looks like that letter, such as a mark made by a person who cannot read or write in lieu of a signature. 

  • Cross, crossing. 

  • The spot behind the goal. 

  • Ecstasy, a particular street drug. 

name
  • A surname, used by those who have had their identity or heritage, including their proper ancestral names, erased or forgotten. 

  • Christ 

  • A placeholder for an unknown, suppressed or hypothetical name. 

num
  • An unknown quantity or unknown value. 

character
  • The twenty-fourth letter of the English alphabet, called ex and written in the Latin script. 

adj
  • Obscene. 

  • Intersex or non-binary (in passports and identification documents). 

es

noun
  • The name of the Cyrillic script letter С / с. 

How often have the words X and es occurred in a corpus of books? (source: Google Ngram Viewer )