hallucination vs pelmanism

hallucination

noun
  • The act of hallucinating; a wandering of the mind; an error, mistake or blunder. 

  • A confident but incorrect response given by an artificial intelligence. 

  • A sensory perception of something that does not exist, often arising from disorder of the nervous system, as in delirium tremens. 

pelmanism

noun
  • A system of training to improve the memory. 

  • A memory card game in which a pack of cards is spread out face-down and players try to turn up pairs with the same symbol. 

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