noun the series of vertebrae forming the axis of the skeleton and protecting the spinal cord.
— synonyms: spinal_column, vertebral_column, spine, back, rachis
noun 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.
— synonyms: spine
noun the part of a network that connects other networks together.
Examples
“Before automobiles, railroads were a backbone of commerce.”
“He would make a good manager, if he had a little more backbone.”