From WordNet (r) 3.0 (2006):
spine
n 1: the series of vertebrae forming the axis of the skeleton
and protecting the spinal cord; "the fall broke his back"
[syn: spinal column, vertebral column, spine,
backbone, back, rachis]
2: any sharply pointed projection [syn: spur, spine,
acantha]
3: a small sharp-pointed tip resembling a spike on a stem or
leaf [syn: spine, thorn, prickle, pricker, sticker,
spikelet]
4: 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; "the title and author were printed on the spine of
the book" [syn: spine, backbone]
5: a sharp rigid animal process or appendage; as a porcupine
quill or a ridge on a bone or a ray of a fish fin