closeout vs unloading

closeout

noun
  • A sale in which all merchandise is sold, at whatever reduced price is necessary 

  • A wave which breaks all at once, as opposed to breaking progressively along its length. 

unloading

noun
  • The act by which something is unloaded. 

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