azygos az·y·gos (āz'ĭ-gŏs', ā-zī'gŏs')
An unpaired anatomical structure. adj. or a·zy·gous (ā-zī'gəs)
Not one of a pair, as a vein or muscle; occurring singly.
This discovery of a tuberculosis of the blood-vessels was confirmed by Klebs, who had found a tuberculosis of the azygos veins.
The vertebral and segmental venous system, representing the azygos veins of the mammalia, is very rudimentary (Figs. 266 and 267).
The Edentates, at any rate the American forms, have a double vena cava posterior and no azygos vein.
In Halmaturus bennettii there are two azygos veins, one left and one right, of which the left is rather the larger.