What does "spine" mean?

Spine: (Zoöl.) (a) A rigid and sharp projection upon any part of an animal. (b) One of the rigid and undivided fin rays of a fish.

Additional senses

  1. 2.(Anat.) The backbone, or spinal column, of an animal; -- so called from the projecting processes upon the vertebræ.
  2. 3.Anything resembling the spine or backbone; a ridge.

Sources