 When used as food for humans, the thymus of animals is known as one of the kinds of sweetbread.The thymus was known to the ancient Greeks, and its name comes from the Greek word θυμός ("thumos"), meaning "anger", or "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" (also in Greek "θύμος" or "θυμάρι"), which became the name for a "warty excrescence", possibly due to its resemblance to a bunch of thyme.Galen was the first to note that the size of the organ changed over the duration of a person's life.