backbone

noun

1. 1

   the part of a network that connects other networks together

   the backbone is the part of a communication network that carries the heaviest traffic

2. 2

   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

3. 3

   fortitude and determination

   he didn't have the guts to try it

4. 4

   the series of vertebrae forming the axis of the skeleton and protecting the spinal cord

   the fall broke his back

5. 5

   a central cohesive source of support and stability

   faith is his anchor

   the keystone of campaign reform was the ban on soft money