lead-in vs prior

lead-in

noun
  • A short phrase that begins the caption of a photograph. 

  • An introduction; something that leads into the beginning of something. 

  • A region of data at the beginning of a compact disc, holding the table of contents. 

prior

adv
  • Previously. 

adj
  • Former, previous. 

  • Advance; previous; coming before. 

noun
  • A high-ranking member of a monastery, usually lower in rank than an abbot. 

  • A prior probability distribution, one based on information or belief before additional data is collected. 

  • A belief supported by previous evidence or experience that one can use to make inferences about the future. 

  • A chief magistrate in Italy. 

  • A previous arrest or criminal conviction on someone's record. 

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