n. 1 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. 2 Zool. & Bot. any hard pointed process or structure. 3 a sharp ridge or projection, esp. of a mountain range or slope. 4 a central feature, main support, or source of strength. 5 the part of a book's jacket or cover that encloses the page-fastening part and usu. faces outwards on a shelf. spine-chiller a frightening story, film, etc. spine-chilling (esp. of a story etc.) frightening. spined adj.
[ ME f. OF espine or L spina thorn, backbone ]