euchologion vs intro

euchologion

noun
  • A book of prayers or religious ritual. 

intro

noun
  • An introduction. 

  • The opening sequence at beginning of a film, television program, etc. 

  • A small demo produced to promote one's demogroup or for a competition. 

verb
  • To introduce. 

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