noun (n)

• the series of vertebrae forming the axis of the skeleton and protecting the spinal cord(noun.body)

  Synonym:
  back, backbone, rachis, spinal column, vertebral column
  

  source: wordnet30
• any sharply pointed projection(noun.shape)

  Synonym:
  acantha, spur
  

  source: wordnet30
• a small sharp-pointed tip resembling a spike on a stem or leaf(noun.plant)

  Synonym:
  pricker, prickle, spikelet, sticker, thorn
  

  source: wordnet30
• 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(noun.artifact)

  Example:
  The title and author were printed on the spine of the book.
  

  Synonym:
  backbone
  

  source: wordnet30
• 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.animal)

  source: wordnet30
• A sharp appendage to any of a plant; a thorn.(noun)

  source: webster1913