entity vs illusion

entity

noun
  • The existence of something considered apart from its properties. 

  • That which has a distinct existence as an individual unit. Often used for organisations which have no physical form. 

  • Anything about which information or data can be stored in a database; in particular, an organised array or set of individual elements or parts. 

  • The state or quality of being or existence. 

  • An alien lifeform that has no corporeal body. 

  • A spirit, ghost, or the like. 

illusion

noun
  • Anything that seems to be something that it is not. 

  • A misapprehension; a belief in something that is in fact not true. 

  • A magician’s trick. 

  • The state of being deceived or misled. 

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