Literal meaning:
* The backbone of the human body is made up of the spine.
* The backbone of the building is the central support structure.
Figurative meaning:
* The backbone of our team is our strong defense.
* The backbone of the community is its dedicated volunteers.
* She has the backbone to stand up for what she believes in, even when it's unpopular.
* The company needs to have a backbone and make tough decisions.
Idiom:
* She had the backbone to tell her boss that she deserved a raise.