Spine

The spine is the line of bones down the middle of your back that supports your body and protects your spinal cord. It also refers to anything shaped like a backbone, such as the stiff edge of a book.

From Middle English “spine,” from Old French “espine,” from Latin “spina” meaning “thorn, backbone.” The original idea was a sharp point or thorn, which later became the word for the bony ridge of the back.