first night vs intro

first night

noun
  • The first public performance of a play or other show, normally assumed to be held in the evening. 

  • The first night after marriage. 

  • Used other than figuratively or idiomatically: see first, night. 

intro

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

  • An introduction. 

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

verb
  • To introduce. 

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