mirror vs pole star

mirror

noun
  • An object, person, or event that reflects or gives a picture of another. 

  • A disk, website or other resource that contains replicated data. 

  • A mirror carp. 

  • A kind of political self-help book, advising kings, princes, etc. on how to behave. 

  • A smooth surface, usually made of glass with reflective material painted on the underside, that reflects light so as to give an image of what is in front of it. 

verb
  • Of an event, activity, behaviour, etc, to be identical to; to be a copy of. 

  • To reflect, as in a mirror. 

  • To create something identical to (a web site, etc.). 

pole star

noun
  • A person, principle, or thing which acts as a guide; a guiding light; also, something which attracts much attention; a centre of attention. 

  • The star visible to the naked eye which was in the past, is now, or will be in the future nearest a celestial pole of a planet. 

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