minder vs registered nurse

minder

noun
  • A monitor assigned by the authorities to someone, such as a foreign visitor (to exercise control over their contacts with the populace) or a journalist or someone who is speaking to journalists (to monitor and control what they say). 

  • One who minds, tends, or watches something such as a child, a machine, or cattle; a keeper. 

  • A personal bodyguard. 

registered nurse

noun
  • A professional nurse who is a licensed graduate of a university or college of nursing who has successfully passed an examination such as NCLEX-RN. 

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