Spine (?), n. [L. spina thorn, the spine; akin to spica a point: cf. OF. espine, F. 'epine. Cf. Spike, Spinet a musical instrument, Spinny.]
1. Bot.
A sharp appendage to any of a plant; a thorn.
2. Zool. (a)
A rigid and sharp projection upon any part of an animal.
(b)
One of the rigid and undivided fin rays of a fish.
3. Anat.
The backbone, or spinal column, of an animal; -- so called from the projecting processes upon the vertebrae.
4.
Anything resembling the spine or backbone; a ridge.
© Webster 1913.