by-product vs resource

by-product

noun
  • A side effect. 

  • A secondary product; something made incidentally during the production of something else. 

resource

verb
  • To source anew or differently; to find or provide a new source for. 

  • To supply with resources. 

noun
  • Something that one uses to achieve an objective, e.g. raw materials or personnel. 

  • Something that can be used to help achieve an aim, especially a book, equipment, etc. that provides information for teachers and students. 

  • A person's capacity to deal with difficulty. 

  • Hardware or software accessible by a computer, network, or another object connected to a computer. 

How often have the words by-product and resource occurred in a corpus of books? (source: Google Ngram Viewer )