cerberus vs watchdog

cerberus

watchdog

verb
  • To perform a function analogous to that of a watchdog; to guard and warn. 

  • To be continuously reset by a watchdog timer. 

noun
  • An individual or group that monitors the activities of another entity (such as an individual, corporation, non-profit group, or governmental organization) on behalf of the public to ensure that entity does not behave illegally or unethically. 

  • A guard dog. 

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