cicerone vs lodestar

cicerone

noun
  • A guide who accompanies visitors and sightseers to museums, galleries, etc., and explains matters of archaeological, antiquarian, historic or artistic interest.. 

lodestar

noun
  • A guiding tenet or principle. 

  • A star used as a navigation reference, particularly a pole star such as Polaris. 

  • A calculated amount to award as attorney's fees derived by multiplying the reasonable number of hours spent working on a case by the reasonable hourly billing rate. 

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