1. (

• spinal_column ,
• vertebral_column ,
• spine ,
• backbone ,
• back ,
• rachis

) the series of vertebrae forming the axis of the skeleton and protecting the spinal cord; "the fall broke his back" ;

2. (

• spur ,
• spine ,
• acantha

) any sharply pointed projection ;

3. (

• spine ,
• thorn ,
• prickle ,
• pricker ,
• sticker ,
• spikelet

) a small sharp-pointed tip resembling a spike on a stem or leaf ;

4. (

• spine ,
• backbone ,

) 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" ;

5. (

• spine

) a sharp rigid animal process or appendage; as a porcupine quill or a ridge on a bone or a ray of a fish fin ;