- rachis - axis of a compound leaf or compound inflorescence
--1 is a kind of axis
- spinal column, vertebral column, spine, backbone, back, rachis - the series of vertebrae forming the axis of the skeleton and protecting the spinal cord; "the fall broke his back"
--2 is a kind of skeletal structure
--2 is a part of axial skeleton
--2 has parts:
--2 has particulars: notochord; chinespinal canal, vertebral canal, canalis vertebralis; coccyx, tail bone; vertebra; intervertebral disc, intervertebral disk - spinal column, vertebral column, spine, backbone, back, rachis - the series of vertebrae forming the axis of the skeleton and protecting the spinal cord; "the fall broke his back"