Definitions of spine:

• noun:   a sharp rigid animal process or appendage; as a porcupine quill or a ridge on a bone or a ray of a fish fin
• noun:   a sharp-pointed tip on a stem or leaf
• noun:   any pointed projection
• noun:   the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
• name:  A surname (very rare: popularity rank in the U.S.: #67628)