Your backbone is the column of connected bones that runs down the center of your back, protecting your spinal cord and giving your body its basic structure. Without your backbone, you'd collapse like a puppet with cut strings. Scientists call it the spine or spinal column, and it's made up of 33 small bones called vertebrae stacked on top of each other like a tower of spools.

The word also describes inner strength and courage. When someone shows backbone, they stand up for what's right even when it's difficult or unpopular. A student who tells the truth about breaking a window, even knowing they'll face consequences, is showing backbone. A person who keeps trying after failing several times demonstrates real backbone.

You might hear that someone “has no backbone” when they can't stand up for themselves or give in too easily to pressure. This doesn't mean anything about their actual spine: it means they lack the courage to hold firm when challenged. Conversely, calling someone “the backbone of the team” means they provide essential strength and support that holds everything together, like how your actual backbone holds up your body.