High Quality Content by WIKIPEDIA articles! In human anatomy, the thymus is an organ located in the upper anterior portion of the chest cavity just behind the sternum. The main function of the thymus is to provide an area for T cell maturation, and is vital in protecting against autoimmunity.The thymus was known to the Ancient Greeks, and its name comes from the Greek word ????? (thumos), meaning heart, soul, desire, life - possibly because of its location in the chest, near where emotions are subjectively felt; or else the name comes from the herb thyme, which became the name for a "warty excrescence", possibly due to its resemblance to a bunch of thyme.