1. One of the bony segments of the spinal column: "Vertebrae are the thirty-three bones of the spinal column, including the seven cervical, twelve thoracic, five lumbar, five sacral, and four coccygeal spinal bones."
2. Any of the bones or cartilaginous segments forming the spinal column.
3. A bone of the spinal column, typically consisting of a thick body, a bony arch enclosing a hole for the spinal cord, and stubby projections which connect with adjacent bones.