sentinel vs varan

sentinel

noun
  • A sentinel crab. 

  • A unique string of characters recognised by a computer program for processing in a special way; a keyword. 

  • A sentry, watch, or guard. 

  • A sign of a health risk (e.g. a disease, an adverse effect). 

verb
  • To post as guard. 

  • To post a guard for. 

  • To watch over as a guard. 

varan

noun
  • The monitor lizard. 

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