- 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"
- fortitude and determination;
"he didn't have the guts to try it"
- the series of vertebrae forming the axis of the skeleton and protecting the spinal cord;
"the fall broke his back"
- 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 part of a network that connects other networks together;
"the backbone is the part of a communication network that carries the heaviest traffic"
