Definition of "spine"

If you attentively regard almost any quadruped's spine, you will be struck with the resemblance of its vertebrae to a strung necklace of dwarfed skulls.

1851, Herman Melville, chapter 80, in Moby-Dick

The preposterous altruism too! […] Resist not evil. It is an insane immolation of self—as bad intrinsically as fakirs stabbing themselves or anchorites warping their spines in caves scarcely large enough for a fair-sized dog.

1918, W. B. Maxwell, chapter 34, in The Mirror and the Lamp‎, page 266

[Describing scoliosis.] The integuments over the abdomen are folded or wrinkled, the left breast is seldom fully developed, the ribs lose their natural shape, those of the left side becoming straighter, while, on the right side, they are so much curved, as to admit of their being easily grasped by the hand; they are closer together on the left side, and frequently rest upon the spine of the ilium, thus giving the right side a fuller and more rounded appearance than is natural.

1838, Samuel Hare, chapter 4, in Practical Observations on the Causes and Treatment of Curvatures of the Spine: With Hygienic Directions for the Physical Culture of Youth, as a Means of Preventing the Disease; an Etching and Description of an Apparatus for the Correction of the Deformity, and Engravings Illustrative of the Cases‎, London: Simpkin, Marshall & Co. [et al.], Lateral Curvature, page 76

The posterior muscles of the neck are divided into superficial, intermediate, and deep groups. The most superficial muscle is the trapezius, which originates from the external occipital protuberance and the medial nuchal line of C7 to T12 spinous processes and inserts onto the spine of the scapula, acromion, and the lateral aspect of the clavicle.

1994, Howard S. An with J. Michael Simpson, “Anatomy of the Cervical Spine”, in Surgery of the Cervical Spine, London: Martin Dunitz, Muscles and Fascia, page 14

The eastern tower and the smaller western satellite are linked by the lift core, which passes through the centre of the monorail turning circle and provides the structural spine of the building; the two towers are cantilevered from this spine.

2007, Peter Hyatt, “Ian Moore Architects”, in Masters of Light: Designing the Luminous House, Mulgrave, Vic.: The Images Publishing Group, Air Apartments, page 242

The polyhedron P∪D is a special spine of the twice punctured M, that is, of M with two balls B1, B2 cut out of it. To get a spine of M, we make a hole in c′ or c″ depending on which of them is a common face of these balls.

2007, Sergei Matveev, “2 Complexity Theory of 3-Manifolds”, in Algorithmic Topology and Classification of 3-Manifolds, 2nd edition, Berlin: Springer Science+Business Media, 2.3.2 Simplification Moves, page 75

The spine is the book's backbone. Because the spine is generally all you can see when a book is on the shelf, the spine displays the title and author of the book and is often ornately decorated.

1994–2014, “Rare Book Basics: Book Terms Illustrated”, in Powell's City of Books‎, archived from the original on 5 July 2014

The male, as Dr. Gunther informs me, has a cluster of stiff, straight spines, like those of a comb, on the sides of the tail.

1871, Charles Darwin, “chapter 12”, in Descent of Man, page 331

Spines are distinguished by the presence of globular tips called spine heads; when spines are present, the synapses innervating dendrites are made from these heads.

2008, Dale Purves, George J. Augustine, David Fitzpatrick, William C. Hall, Anthony-Samuel LaMantia, James O. McNamara, Leonard E. White, Neuroscience, 4th edition, Sinauer Associates