backbone
back-bone
noun
The column of bones down the back, supporting the body.
"He injured his backbone playing rugby."
noun
The most important supporting part of a system or organisation.
"Small businesses are the backbone of the local economy."
noun
Strength of character, courage, or determination to stand firm.
"She showed real backbone during the difficult negotiations."
Thesaurus
Synonyms: spine, vertebral column, rachis, spinal column, back, anchor, mainstay, keystone, linchpin, lynchpin, moxie, sand