feed vs retain

feed

verb
  • To supply with something. 

  • To graze; to cause to be cropped by feeding, as herbage by cattle. 

  • To give to a machine to be processed. 

  • To create the environment where another phonological rule can apply; to be applied before another rule. 

  • To create the syntactic environment in which another syntactic rule is applied; to be applied before another syntactic rule. 

  • To pass to. 

  • To satisfy, gratify, or minister to (a sense, taste, desire, etc.). 

  • To give (someone or something) food to eat. 

  • To eat (usually of animals). 

  • To give (someone or something) to (someone or something else) as food. 

noun
  • The part of a machine that supplies the material to be operated upon. 

  • Something supplied continuously. 

  • Food given to (especially herbivorous) non-human animals. 

  • A meal. 

  • A gathering to eat, especially in large quantities. 

  • Encapsulated online content, such as news or a blog, that can be subscribed to. 

  • A straight man who delivers lines to the comedian during a performance. 

  • The forward motion of the material fed into a machine. 

retain

verb
  • To keep in possession or use. 

  • To employ by paying a retainer. 

  • To hold back (a pupil) instead of allowing them to advance to the next class or year. 

  • To keep in one's pay or service. 

  • To hold secure. 

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