backbone

Noun

• the part of a network that connects other networks together
  • the backbone is the part of a communication network that carries the heaviest traffic
    

• the part of a book's cover that encloses the inner side of the book's pages and that faces outward when the book is shelved
  • the title and author were printed on the spine of the book
    

• the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
  • the fall broke his back
    

• fortitude and determination
  • he didn't have the guts to try it
    

• a central cohesive source of support and stability
  • faith is his anchor
    
  • the keystone of campaign reform was the ban on soft money
    
  • he is the linchpin of this firm
    

Related words

• Synonyms: 
  spine , spinal column , vertebral column , back , rachis , grit , guts , moxie , sand , gumption , anchor , mainstay , keystone , linchpin , lynchpin