To turn on axis?
There are many things that can turn on an axis in this world. Turning on an axis is called rotation.
The axis is the second of the seven bones in the cervical spine (neck). The axis, also known as the C2 bone, creates a pivot that allows the C1, or atlas, to turn. It has a tooth like structure that allows the first bone called the atlas to turn. Since the skull actually is held up by the atlas, this joint allows the person to turn their head.