aid vs foster

aid

verb
  • To provide support to; to further the progress of; to help; to assist. 

  • To climb with the use of aids such as pitons. 

noun
  • Help; assistance; succor, relief. 

  • An historical subsidy granted to the crown by Parliament for an extraordinary purpose, such as a war effort. 

  • A helper; an assistant. 

  • An exchequer loan. 

  • Something which helps; a material source of help. 

  • A pecuniary tribute paid by a vassal to his feudal lord on special occasions. 

  • The rider's use of hands, legs, voice, etc. to control the horse. 

foster

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

  • To cultivate and grow something. 

  • To nurse or cherish something. 

noun
  • A foster parent. 

  • The care given to another; guardianship. 

adj
  • Related by such care. 

  • Receiving such care. 

  • Providing parental care to children not related to oneself. 

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