Vena Azygos is a medical term used to describe a large vein that connects to the superior vena cava, which carries blood from the upper body to the heart. This vein is important in the proper functioning of the circulatory system, and there are a few different synonyms that can be used to describe it. Some of the most commonly used synonyms for Vena Azygos include the azygos vein, azygos system, and azygos arch. These terms all refer to the same vein, which is located in the thorax area of the body and is essential for the proper flow of blood throughout the body.