libretto vs verse

libretto

noun
  • A book containing such a text. 

  • The text of a dramatic musical work, such as an opera. 

verse

noun
  • A small section of a holy book (Bible, Quran etc.) 

  • A poetic form with regular meter and a fixed rhyme scheme. 

  • One of several similar units of a song, consisting of several lines, generally rhymed. 

  • A portion of an anthem to be performed by a single voice to each part. 

  • Poetic form in general. 

verb
  • to educate about, to teach about. 

  • To oppose, to compete against, especially in a video game. 

  • To tell in verse, or poetry. 

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