closedown vs shutdown

closedown

noun
  • The point when a radio or television station shuts down transmission and goes off the air for a predetermined period, as used to happen overnight. 

shutdown

noun
  • The action of stopping operations; a closing, of a computer, business, event, etc. 

  • A statement, insult, etc. that prevents the opponent from replying further. 

  • An autistic response to stress or sensory overload, in which the individual freezes up and becomes silent, motionless, and unresponsive. 

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