babysitter vs wet nurse

babysitter

noun
  • A person who cares for one or more babies or children for a short period of time in place of their legal guardians. 

wet nurse

noun
  • Someone who treats someone else with excessive care. 

  • A woman hired to suckle another woman's child. 

verb
  • To act as a wet nurse (in either sense). 

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