dog sleep vs hypnosis

dog sleep

noun
  • A shallow sleep; a pretended sleep. 

hypnosis

noun
  • Any of various sleep-like conditions. 

  • The art or skill of hypnotism. 

  • A trancelike state, artificially induced, in which a person has a heightened suggestibility, and in which suppressed memories may be experienced. 

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