a 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.
the part of a book's jacket or cover that encloses the inner edges of the pages, facing outward when the book is on a shelf and typically bearing the title and the author's name.
3
Zoology
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.
