spine
n. countablen. the row of bones that goes down the middle of your back and supports your body. It also refers to the hard back part of a book where the title is written.
n. the series of vertebrae extending from the skull to the pelvis, forming the main support of the body. Also refers to the back part of a book binding that connects the covers.
Keep your spine straight when you sit at your desk.
The doctor examined the patient's spine to see if the injury had affected the nerves in his lower back.
The library's rare collection was so fragile that even opening a volume risked cracking the leather spine and loosening the hand-stitched pages within.
From late Middle English spyne, from Old French espine (French épine) or its source, Latin spīna (“a thorn; a prickle, spine; the backbone”). Doublet of spina.
Often used in the phrase 'chills down one's spine' to describe a feeling of fear or excitement.