foretoken vs omen

foretoken

verb
  • To betoken beforehand; prognosticate; foreshadow; give warning of; presage. 

noun
  • A prognostic; a premonitory sign; warning or presentiment. 

omen

verb
  • To divine or predict from omens. 

  • To be an omen of. 

noun
  • A thing of prophetic significance. 

  • Something which portends or is perceived to portend either a good or evil event or circumstance in the future, or which causes a foreboding; a portent or augury. 

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