the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
"the fall broke his back"
the part of a network that connects other networks together
"the backbone is the part of a communication network that carries the heaviest traffic"
The series of vertebrae, separated by disks, that encloses and protects the spinal cord, and runs down the middle of the back in vertebrate animals.
"The surgeon carefully examined the patient's backbone to ensure the spinal cord was fully protected before performing the operation."
In plain English: The backbone is your spine, which supports and protects your body's nerves.
"The strong spine is my body's backbone that supports all movement."
Usage: Use "backbone" metaphorically to describe a person's inner strength or resolve when facing difficulties. Avoid confusing it with literal physical support structures unless specifically discussing anatomy.
The word "backbone" comes from Middle English, formed by combining "back" and "bone." It originally referred literally to the bones that support a person's back.