azygos vein
Anatomical term for the vein that drains the thoracic wall and upper lumbar region, running along the right side of the vertebral column.
The azygos vein joins the superior vena cava.
The term is composed of 奇 (strange, unusual) and 静脈 (vein), likely a calque from the anatomical term 'azygos' (from Greek 'a-' without + 'zygon' yoke), referring to its unpaired nature.