briefing vs synopsis

briefing

noun
  • A short and concise summary of a situation. 

  • A presentation of information or instruction; the meeting at which it is presented. 

synopsis

noun
  • A brief summary of the major points of a written work, either as prose or as a table; an abridgment or condensation of a work. 

  • A prayer book for use by the laity of the church. 

  • A reference work containing brief articles that taken together give an overview of an entire field. 

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