Spine

·noun A sharp appendage to any of a plant; a thorn.

II. Spine ·noun One of the rigid and undivided fin rays of a fish.

III. Spine ·noun Anything resembling the spine or backbone; a ridge.

IV. Spine ·noun A rigid and sharp projection upon any part of an Animal.

V. Spine ·noun The backbone, or spinal column, of an animal;

— so called from the projecting processes upon the vertebrae.