1a series of vertebrae extending from the skull to the small of the back, enclosing the spinal cord and providing support for the thorax and abdomen; the backbone:a soft voice that sent a shiver down her spine
the central feature or main source of strength of something:players of high quality who will form the spine of our sidePuerto Rico’s mountainous spine
[mass noun] resolution or strength of character.
2the part of a book’s jacket or cover that encloses the inner edges of the pages, facing outwards when the book is on a shelf and typically bearing the title and the author’s name.
3 Zoology & Botany any hard, pointed defensive projection or structure, such as a prickle of a hedgehog, a spike-like projection on a sea urchin, a sharp ray in a fish’s fin, or a spike on the stem of a plant.
4 (also pay spine) a linear pay scale operated by some large organizations that allows flexibility for local and specific conditions.
5 Geology a tall mass of viscous lava extruded from a volcano:the Mt Pelee spine was exceptional only for its extreme height—over 300 metres