1. (noun)back, dorsum the posteriorpart of a human (or animal) body from the neck to the end of the spine "his back was nicely tanned"
2. (noun)rear, back the side that goes last or is not normally seen
"he wrote the date on the back of the photograph"
3. (noun)back, rear the part of something that is furthest from the normalviewer "he stood at the back of the stage"; "it was hidden in the rear of the store"
4. (noun)back (football) a person who plays in the backfield
5. (noun)spinal column, vertebral column, spine, backbone, back, rachis the series of vertebrae forming the axis of the skeleton and protecting the spinalcord "the fall broke his back"
6. (noun)binding, book binding, cover, back the protective covering on the front, back, and spine of a book "the book had a leather binding"
7. (noun)back the part of a garment that covers the back of your body "they pinned a `kick me' sign on his back"
8. (noun)back, backrest a support that you can lean against whilesitting "the back of the dental chair was adjustable"