This aorta is the main and largest artery of the systemic portion of the circulatory system. It is one of the great vessels of the heart. It starts at the ventriculoaortic anulus and ends at its bifurcation of the aorta in front of the body of the 4th lumbar vertebra. At this point the aorta is continuous with the left and right common iliac arteries.

The aorta has four segments: ascending aorta, aortic arch, descending or thoracic aorta, and abdominal aorta.  

The etymology of the term [aorta] is not clear. The first reference of this structure is from Aristotle, who uses the word "aorta", although in the same work he refers to it as the "tendinous vein". Adrian Van Der Spigelius (1578 - 1625) mentions that the name aorta was given to the curved sheath of a Macedonian knife which has a pronouncedly curved handle (the aorta has a pronounced curve at the aortic arch). Yet another interpretation comes from the Greek, where a similar word means a "curved shoulder strap".

Sources:
1. "The origin of Medical Terms" Skinner, AH, 1970
2. "Medical Meanings" Haubrich, William S. Am Coll Phys Philadelphia 1997