spine

背骨, 脊柱, 尖刺

a small sharp-pointed tip resembling a spike on a stem or leaf; the part of a book's cover that encloses the inner side of the book's pages and that faces outward when the book is shelved; a sharp rigid animal process or appendage; as a porcupine quill or a ridge on a bone or a ray of a fish fin

棘刺