babysitter vs foster

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. 

foster

noun
  • The care given to another; guardianship. 

  • A foster parent. 

adj
  • Related by such care. 

  • Receiving such care. 

  • Providing parental care to children not related to oneself. 

verb
  • To cultivate and grow something. 

  • To nurture or bring up offspring, or to provide similar parental care to an unrelated child. 

  • To nurse or cherish something. 

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