Backbone

Dictionary definition

n. 1: 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" [syn: anchor, mainstay, keystone, backbone, linchpin, lynchpin]
2: fortitude and determination; "he didn't have the guts to try it" [syn: backbone, grit, guts, moxie, sand, gumption]
3: the series of vertebrae forming the axis of the skeleton and protecting the spinal cord; "the fall broke his back" [syn: spinal column, vertebral column, spine, backbone, back, rachis]
4: 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" [syn: spine, backbone]
5: the part of a network that connects other networks together; "the backbone is the part of a communication network that carries the heaviest traffic"