backbone vs resistance

backbone

noun
  • Courage, fortitude, or strength. 

  • The series of vertebrae, separated by disks, that encloses and protects the spinal cord, and runs down the middle of the back in vertebrate animals. 

  • Any fundamental support, structure, or infrastructure. 

resistance

noun
  • The act of resisting, or the capacity to resist. 

  • An underground organisation engaged in a struggle for liberation from forceful occupation; a resistance movement. 

  • A force that tends to oppose motion. 

  • electrical resistance. 

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