the spinal or vertebral column; backbone.

any backbonelike part.

a stiff, pointed process or appendage on an animal, as a quill of a porcupine, or a sharp, bony ray in the fin of a fish.

something, as a quality or trait, that constitutes a principal strength; resolution; stamina; backbone

a situation that would test a person's spine.

a ridge, as of ground or rock.

a sharp-pointed, hard or woody outgrowth on a plant; thorn.

Bookbinding . the back of a book cover or binding, usually indicating the title and author.