leading vs pole star

leading

noun
  • An act by which one is led or guided. 

  • Vertical space added between lines; line spacing. 

adj
  • Providing guidance or direction. 

  • Occurring in advance; preceding. 

  • Ranking first. 

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 leading and pole star occurred in a corpus of books? (source: Google Ngram Viewer )