lull vs moratorium

lull

noun
  • A period of reduced activity; a respite 

  • A period of rest or soothing. 

  • A period without waves or wind. 

  • An extended pause between sets of waves. 

verb
  • To cause to rest by soothing influences; to compose; to calm 

  • To become gradually calm; to subside; to cease or abate. 

moratorium

noun
  • A suspension of an ongoing activity. 

  • An authorization to a debtor, permitting temporary suspension of payments. 

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