one of the bony segments of the spinal column
Any of the bony or cartilaginous segments which make up the backbone, consisting in some lower vertebrates of several distinct elements which never become united, and in higher vertebrates having a short more or less cylindrical body whose ends articulate by pads of elastic or cartilaginous tissue with those of adjacent vertebrae and a bony arch that encloses the spinal cord.
The word comes from Latin vertebra, meaning "a joint," which is derived from vertō ("to turn"). This name reflects how the multiple bones in the backbone allow the body to bend and twist rather than remaining rigid.