conclusion vs introduction

conclusion

noun
  • The outcome or result of a process or act. 

  • The end or close of a pleading, for example, the formal ending of an indictment, "against the peace", etc. 

  • In an argument or syllogism, the proposition that follows as a necessary consequence of the premises. 

  • A decision reached after careful thought. 

  • An estoppel or bar by which a person is held to a particular position. 

  • The end, finish, close or last part of something. 

introduction

noun
  • The act or process of introducing. 

  • A written or oral explanation of what constitutes the basis of an issue. 

  • A means, such as a personal letter, of presenting one person to another. 

  • An initial section of a book or article, which introduces the subject material. 

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