reflection vs vacancy

reflection

noun
  • The act of reflecting or the state of being reflected. 

  • The process or mechanism of determining the capabilities of an object at run-time. 

  • The folding of a part; a fold. 

  • Something, such as an image, that is reflected. 

  • The property of a propagated wave being thrown back from a surface (such as a mirror). 

  • Careful thought or consideration. 

  • An implied criticism. 

vacancy

noun
  • Empty space. 

  • An available room in a hotel; guest house, etc. 

  • An unoccupied position or job. 

  • Lack of intelligence or understanding. 

  • A blank mind, unoccupied with thought. 

  • A defect in a crystal caused by the absence of an atom in a lattice 

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