n.
a central cohesive source of support and stability
同义词：anchormainstaykeystonelinchpinlynchpin
fortitude and determination
同义词：gritgutsmoxiesandgumption
the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
同义词：spinal columnvertebral columnspinebackrachis
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
同义词：spine
the part of a network that connects other networks together
"the backbone is the part of a communication network that carries the heaviest traffic"
