abend vs final curtain

abend

noun
  • Termination of a process prior to completion. 

  • The abnormal termination of a program. 

verb
  • To terminate abnormally. 

final curtain

noun
  • The last time the curtain is lowered, after a performance and any curtain calls. 

  • The end to something that has lasted for a long time. 

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