Hypnos comes from the name of his Latin counterpart, Somnus. (in- "not" + somnus "sleep"), as well as a few less-common words such as "somnolent", meaning sleepy or tending to cause sleep and hypersomnia meaning excessive sleep, which can be caused by many conditions (known as secondary hypersomnia) or a rare sleep disorder causing excessive sleep with unknown cause, called Idiopathic Hypersomnia. 3D model of "Bronze head of Hypnos" via laser scan of a cast of British Museum's bronze. Hypnos In Greek mythology, Hypnos (; , "sleep") is the personification of sleep; the Roman equivalent is known as Somnus. In the
Pluto (mythology) . Jupiter got the sky, Neptune got the sea, and Pluto got the shaft." In Riordan's explanation, Hades "was more of a death god," but acquired his identity as a god of wealth among the Romans, along with a new name. Scientific terms derived from the name of Pluto include: Pluto (mythology) Pluto (Latin: "Plūtō"; , "") was the ruler of the underworld in classical mythology. The earlier name for the god was Hades, which became more common as the name of the underworld itself. In ancient Greek religion and mythology, Pluto represents a more positive concept of the god