What is another word for backbone?

There are many words that could be used as a synonym for "backbone," depending on the context. Here are a few options, categorized by meaning:

Physical:

* Spine

* Vertebral column

* Spinal column

* Back

* Dorsal column

Figurative:

* Strength: fortitude, courage, determination, grit, resilience, mettle, spirit

* Integrity: honesty, morality, principle, ethics, virtue

* Leadership: authority, command, control, power, dominance

* Support: foundation, base, structure, framework, pillar

Informal:

* Guts

* Nerve

* Spunk

* Willpower

The best synonym will depend on the specific context and the meaning you want to convey. For example, if you're talking about someone's physical spine, then "vertebral column" would be the most accurate synonym. However, if you're talking about someone's inner strength, then "courage" or "grit" might be more appropriate.