It's attached to covers and sheets (5)
I believe the answer is:
spine
(Other definitions for spine that I've seen before include "Vertebrae, complete" , "Line of vertebrae" , "Vertebral column" , "Series of vertebrae" , "Strength of character" .)
I believe the answer is:
spine
(Other definitions for spine that I've seen before include "Vertebrae, complete" , "Line of vertebrae" , "Vertebral column" , "Series of vertebrae" , "Strength of character" .)