assimilation vs digestive system

assimilation

noun
  • The metabolic conversion of nutrients into tissue. 

  • The act of assimilating or the state of being assimilated. 

  • A sound change process by which the phonetics of a speech segment becomes more like that of another segment in a word (or at a word boundary), so that a change of phoneme occurs. 

  • The adoption, by a minority group, of the customs and attitudes of the dominant culture. 

  • The absorption of new ideas into an existing cognitive structure. 

digestive system

noun
  • A system of organs for the purpose of digesting food. 

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